The Companion Animal Symposium titled "Living Beyond 20: Discoveries in Geriatric Companion Animal Biology" was held at the joint annual meeting of the American Dairy Science Association, and American Society of Animal Science on July 10-14, 2011, in New Orleans, LA. The objectives of this symposium were to 1) explore the scientific discoveries specific to the quality of life, nutrition, and well-being of geriatric companion and exotic animals and 2) to promote future research related to these growing animal populations. Both companion and exotic animals are managed for longevity and conservation, as opposed to production purposes; therefore, both animal populations were included in the symposium.

The objective of this study was to determine the effect of dietary nitrate on methane emission and rumen fermentation parameters in Nellore x Guzera (Bos indicus) beef cattle fed a sugarcane based diet. The experiment was conducted with 16 steers weighing 283 ± 49 kg (mean ± SD), six rumen cannulated and ten intact, in a cross-over design. The animals were blocked according to body weight and presence or absence of rumen cannula and randomly allocated to either the nitrate diet (22 g nitrate/ kg DM) or the control diet made isonitrogenous by the addition of urea. The diets consisted of freshly chopped sugarcane and concentrate (60:40 on DM basis), fed as a mixed ration. A 16-d adaptation period was used to allow the rumen microbes to adapt to dietary nitrate. Methane emission was measured using the sulfur hexafluoride tracer technique. Dry matter intake (P = 0.09) tended to be lower when nitrate was present in the diet compared to the control, 6.60 and 7.05 kg DMI, respectively. The daily methane production was reduced (P < 0.01) by 32% when steers were fed the nitrate diet (85 g/d) compared with the urea diet (125 g/d). Methane emission per kg DMI was 27% lower (P < 0.01) on the nitrate diet (13.3 g methane/kg DMI) than on the control diet (18.2 g methane/kg DMI). Methane losses as a fraction of gross energy intake (GEI) were lower (P < 0.01) on the nitrate diet (4.2% of GEI) than on the control diet (5.9% of GEI). Nitrate mitigated enteric methane production by 87% of the theoretical potential. The rumen fluid ammonia-nitrogen (NH₃-N) concentration was significantly greater (P < 0.05) for the nitrate diet. The total concentration of VFA was not affected by nitrate in the diet, whilst the proportion of acetic acid tended to be greater (P = 0.09), propionic acid lower (P = 0.06) and acetate/propionate ratio tended to be greater (P = 0.06) for the nitrate diet. Dietary nitrate reduced enteric methane emission in beef cattle fed sugarcane based diet.

A mathematical model was developed to investigate the impact of level of Teladorsagia circumcincta larval pasture contamination and anthelmintic treatment on genetic parameter estimates for performance and resistance to parasites in sheep. Currently great variability is seen for published correlations between performance and resistance, with estimates appearing to vary with production environment. The model accounted for host genotype and parasitism in a population of lambs, incorporating heritable between-lamb variation in host-parasite interactions, with genetic independence of input growth and immunological variables. An epidemiological module was linked to the host-parasite interaction module via food intake (FI) to create a grazing scenario. The model was run for a population of lambs growing from 2 months of age, grazing on pasture initially contaminated with 0, 1000, 3000, or 5000 larvae/kg DM, and given either no anthelmintic treatment or drenched at 30 day intervals. The mean population values for FI and empty body weight (EBW) decreased with increasing levels of initial larval contamination (IL₀), with non-drenched lambs having a greater reduction than drenched ones. For non-drenched lambs the maximum mean population values for worm burden (WB) and fecal egg count (FEC) increased and occurred earlier for increasing IL₀, with values being similar for all IL₀ at the end of the simulation. Drenching was predicted to suppress WB and FEC, and cause reduced pasture contamination. The heritability of EBW for non-drenched lambs was predicted to be initially high (0.55) and decreased over time with increasing IL₀, whilst drenched lambs remained high throughout. The heritability of WB and FEC for all lambs was initially low (~0.05) and increased with time to ~0.25, with increasing IL₀ leading to this value being reached at faster rates. The genetic correlation between EBW and FEC was initially ~-0.3. As time progressed the correlation tended towards zero, before becoming negative by the end of the simulation for non-drenched lambs, with increasing IL₀ leading to increasingly negative correlations. For drenched lambs the correlation remained close to zero. This study highlights the impact of IL₀ and anthelmintic treatment on genetic parameters for resistance. Along with factors affecting performance penalties due to parasitism and time of reporting, the results give plausible causes for variation in genetic parameter estimates previously reported.

The objectives of this experiment were to determine the effects of two different breeds (BR) Boer and Kiko, and four post-weaning harvest ages (HA; d 0, 29, 56 and 85) on growth, carcass traits, blood metabolites, and lipogenic gene expression. Forty-eight goat kids (BW = 23.9 ± 1.50 kg; 3-4 mo) were used in a 2 x 4 factorial experiment. Goats were stratified by BW within BR and randomly assign to four HA. Kids were born between March 15 and April 7, to purebred does, and were represented by at least three purebred sires within each breed. They were fed a grain:hay (80:20) diet once a day. At designated HA, randomly pre-assigned goats (n = 6) from each BR were transported to the Meat Science Lab., Mississippi State University, MS and were harvested. There were no interactions between BR and HA. Boer BR tended (P = 0.08) to have greater initial BW, final BW (P = 0.05) and greater G:F ratio (P = 0.05). Although the 80:20 grain:hay diet was reinforced by adjusting DMI, both BRs had similar total DMI, Boer BR kept that ratio, while Kiko BR consumed more (P = 0.001) hay (70:30) and had more DMI when expressed as g/kg BW. Boer BR tended to have greater transportation shrink (P = 0.07), HCW (P = 0.08) and cold carcass weights (CCW; P = 0.08) with greater (P = 0.001) carcass fat. No differences were observed in carcass shrink, dressing percentage, 12^th rib fat thickness, and LM area between two BR. When expressed as % empty BW, carcass bone was similar (P = 0.25), while muscle % (P = 0.02) was greater for Kiko and fat % was greater (P = 0.001) for Boer BR. Fat as a % of CCW remained relatively the same (P > 0.10) for both BR for 2^nd and 3^rd HA. Differences were more evident (P = 0.01) at the 4^th HA. Boer BR reached targeted harvest weight (29 kg) at 3^rd HA while fat deposition continued (P = 0.01) during 4^th HA. Breed had no effect on meat color (L^*, a^*, b^*) but HA affected (P = 0.001) all color values. Boer BR had similar 3-hydroxyl-3-methylglutaryl-CoA synthase mRNA abundance, but was greater (P < 0.03) in acetyl CoA carboxylase compared to Kiko BR. There was no difference (P = 0.52) in total serum fatty acids (mg/mL) between the two breeds. As animals aged, their total serum fatty acids increased (P < .05) and changed to an undesirable profile. Kiko BR had a greater percentage of muscle and less fat in the carcass. We concluded that different breeds might need different harvest endpoints and feed input according to the consumer acceptability.

A 2-yr study was conducted using a 3 x 2 factorial arrangement of treatments to evaluate the effects of feeding dried distillers grains throughout a beef production system on performance, carcass characteristics, and fatty acid profile of beef. Factors were wheat pasture supplement (no supplement, dry-rolled corn, and dried distillers grains; CON, DRC, and DDG, respectively) fed at 0.5% BW daily and finishing diet (steam-flaked corn based diet containing 0 or 35% DDG; SFC and 35DDG, respectively). Each yr, 60 preconditioned Hereford steers (initial BW = 198 kg ± 3) grazed winter wheat pasture with or without supplement. Gain was 8% greater for steers consuming DDG supplement compared to CON and DRC steers (P < 0.01). Following the grazing period, pastures within supplement treatment were randomly assigned to SFC or 35DDG. There was no supplement by finishing diet interaction for any performance or carcass variable of interest (P ≥ 0.41). Previous supplementation on winter wheat affected BW at feedlot entry and adjusted G:F (P ≤ 0.05) but had no effect on finishing ADG or carcass traits (P ≥ 0.12). On a carcass-adjusted basis, steers consuming 35DDG had reduced final BW, ADG, G:F, and total gain throughout the system (P ≤ 0.04) compared to SFC. Additionally, steers consuming 35DDG had reduced HCW, dressing percent, and fat thickness (P ≤ 0.03) compared to SFC. There was a supplement by finishing diet interaction (P = 0.02) for 18:0, in which cattle supplemented with DRC and fed the SFC finishing diet had the lowest concentration of 18:0 but DRC supplemented steers fed the 35DDG diet had the highest concentration. The interaction was not significant (P ≥ 0.18) for other fatty acids. Main effects of supplement and finishing diet affected (P ≤ 0.05) several other fatty acids of interest, particularly 18:2, which is associated with reduced flavor-stability of beef. The use of DDG as a supplement to wheat pasture resulted in greater ADG during wheat grazing and heavier BW at feedlot entry, but final BW was not different from CON or DRC groups. Feeding DDG at 35% DM in steam-flaked corn-based finishing diets reduced ADG, G:F, and HCW, and affected the fatty acid composition of beef.

Minimal quantities of ruminally degradable protein from supplements may improve supplement utilization efficiency of ruminants grazing dormant forages. In Exp. 1, N retention, ruminal NH₃, serum urea N, and NDF digestibility was evaluated for 12 ruminally cannulated cows in an incomplete Latin Square design with 3 periods of 42 d each. Cows were fed weeping lovegrass hay (4.1% CP, 75% NDF, OM basis) at 1.3% BW/d and offered 1 of 3 sources of CP (urea, UREA; cottonseed meal, CSM; or 50% blood meal, 50% feather meal combination, BFM) fed to supply 0, 40, 80, or 160 g/d of CP. Beginning on d 22 of supplementation, ruminal contents and serum samples were collected at -2, 0, 3, 6, 9, 12, 18, 24, 30, 36, and 48 h relative to the morning offering of hay. On d 24, feces and urine were collected for 72 h. In Exp. 2, four ruminally cannulated steers were used in a replicated 4 x 4 Latin Square to evaluate utilization of supplements differing in quantity and ruminal CP degradability. Steers were fed 6.8 kg/d chopped sudangrass hay (3.7% CP, 74% NDF on OM basis) and supplemented with 56 g/d of a salt mineral mix (CON); CON + 28 g/d blood meal + 28 g/d feather meal (BFM); CON + 98 g/d CSM (LCS); or CON + 392 g/d CSM (HCS). Treatments provided 0, 40, 40, or 160 g/d of CP for CON, BFM, LCS, and HCS; respectively. In Exp. 1, N utilization and total tract NDF digestibility were not affected by protein sources or levels (P > 0.18). Ruminal NH₃ concentrations exhibited a quadratic response over time for UREA (P < 0.05) and was greater with increasing levels of UREA (P < 0.05); whereas BFM or CSM did not differ (P > 0.05) by level or across time. In Exp. 2, supplementation had a tendency (P = 0.09) to increase DM disappearance. Supplementation also increased (P < 0.01) serum glucose concentrations; however, no difference (P > 0.28) was found between supplements. Serum urea N and ruminal NH₃ concentrations were increased (P < 0.01) in steers fed HCS. Feeding low quantities of a high-RUP supplement maintained rumen function without negatively affecting DM or NDF digestibility of a low-quality forage diet.

The objective of this study was to develop and evaluate a mathematical model used to estimate the daily energy and nutrient requirements of individual growing-finishing pigs. The model includes empirical and mechanistic model components. The empirical component estimates daily feed intake (DFI), BW, and daily gain (DG) based on individual pig information collected in real-time. Based on DFI, BW, and DG estimates, the mechanistic component uses classic factorial equations to estimate the optimal concentration of amino acids that must be offered to each pig to meet its requirements. The model was evaluated with data from a study that investigated the effect of feeding pigs with a 3-phase or daily multiphase system. The DFI and BW values measured in this study were compared with those estimated by the empirical component of the model. The coherence of the values estimated by the mechanistic component was evaluated by analyzing if it followed a normal pattern of requirements. Lastly, the proposed model was evaluated by comparing its estimates with those generated by the existing growth model (InraPorc). The precision of the proposed model and InraPorc in estimating DFI and BW was evaluated through the mean absolute error. The empirical component results indicated that the DFI and BW trajectories of individual pigs fed ad libitum could be predicted 1 (DFI) or 7 d (BW) ahead with the average mean absolute error of 12.45 and 1.85%, respectively. The average mean absolute error obtained with the InraPorc for the average individual of the population was 14.72% for DFI and 5.38% for BW. Major differences were observed when estimates from InraPorc were compared with individual observations. The proposed model, however, was effective in following the change in DFI and BW for each individual pig. The mechanistic model component estimated the optimal standardized ileal digestible Lys to NE ratio with reasonable between animal (average CV = 7%) and overtime (average CV = 14%) variation. Thus, the energy and nutrient requirements estimated by model are animal and time dependent and follow, in real-time, the individual DFI and BW growth patterns. The proposed model can follow the average feed intake and feed weight trajectory of each individual pig in real-time with good accuracy. Based on these trajectories and using classical factorial equations, the model makes it possible to estimate dynamically each individual’s energy and nutrient requirements, taking into account animal’s intake and growth changes.

Three experiments were conducted to determine the Val and Ile requirements in low-CP, corn-soybean meal (C-SBM) AA-supplemented diets for 20- to 45-kg pigs. All experiments were conducted for 26 to 27 d with purebred or crossbred barrows and gilts, which were blocked by initial BW. Treatments were replicated with 5 or 6 pens of 3 or 4 pigs per pen. At the beginning of Exp. 1 and the end of all experiments, blood samples were obtained from all pigs to determine plasma urea N (PUN) concentrations. All diets were C-SBM with 0.335% supplemental Lys to achieve 0.83% standardized ileal digestible (SID) Lys, which is the Lys requirement of these pigs. In Exp. 1, 0, 0.02, 0.04, 0.06, 0.08, or 0.10% L-Val was supplemented to achieve 0.51, 0.53, 0.55, 0.57, 0.59, or 0.61% dietary SID Val, and Thr, Trp, Met, Ile were supplemented to maintain Thr:Lys, Trp:Lys, TSAA:Lys, and Ile:Lys of 0.71, 0.20, 0.62, and 0.60, respectively. Also, supplemental Gly and Glu were added to all diets to achieve 1.66% Gly + Ser and 3.28% Glu, which is equal to the Gly + Ser and Glu content of a previously validated positive control diet that contained no supplemental AA. Treatment differences were considered significant at P < 0.10. Valine addition increased ADG, ADFI, and G:F in pigs fed 0.51 to 0.59% SID Val (linear, P < 0.08), but ADG and ADFI were decreased at 0.61% SID Val (quadratic, P ≤ 0.10). Based on ADG and G:F, the SID Val requirement is between 0.56 and 0.58% in a C-SBM diet supplemented with AA. In Exp. 2 and 3, 0, 0.02, 0.04, 0.06, or 0.08% L-Ile was supplemented to achieve 0.43, 0.45, 0.47, 0.49, or 0.51% dietary SID Ile, and Thr, Trp, Met, and Ile were supplemented to maintain Thr:Lys, Trp:Lys, TSAA:Lys, and Val:Lys of 0.71, 0.20, 0.62, and 0.74, respectively. Also, supplemental Gly and Glu were added to achieve 1.66% Gly + Ser and 3.28% Glu as in Exp. 1. Data from Exp. 2 and 3 were combined and analyzed as one data set. Daily gain, ADFI, and G:F were not affected by Ile additions to the diet; however, ADFI was decreased among pigs fed the diet with 0.45% SID Ile (P < 0.10) compared with pigs fed the 0.43% SID Ile diet. Broken-line analysis requirements could not be estimated for the combined data from Exp. 2 or 3. The results of this research indicate that the SID Val requirement is between 0.56 to 0.58% (0.67 to 0.70 SID Val:Lys), and the Ile requirement is adequate at 0.43% SID Ile (0.52 SID Ile:Lys) for 20- to 45-kg pigs.

The natural diet of felids contains highly digestible animal tissues but also fractions resistant to small intestinal digestion, which enter the large intestine where they may be fermented by the resident microbial population. Little information exists on the microbial degradability of animal tissues in the large intestine of felids consuming a natural diet. This study aimed to rank animal substrates in their microbial degradability by means of an in vitro study using captive cheetahs fed a strict carnivorous diet as fecal donors. Fresh cheetah fecal samples were collected, pooled, and incubated with various raw animal substrates (chicken cartilage, collagen, glucosamine-chondroitin, glucosamine, rabbit bone, rabbit hair, and rabbit skin; 4 replicates per substrate) for cumulative gas production measurement in a batch culture technique. Negative (cellulose) and positive (casein and fructo-oligosaccharides; FOS) controls were incorporated in the study. Additionally, after 72 h of incubation, short-chain fatty acids (SCFA), including branched-chain fatty acids (BCFA), and ammonia concentrations were determined for each substrate. Glucosamine and glucosamine-chondroitin yielded the greatest OM cumulative gas volume (OMCV) among animal substrates (P < 0.05), whereas total SCFA production was greatest for collagen (P < 0.05). Collagen induced an acetate production comparable to FOS and a markedly high acetate-to-propionate ratio (8.41:1) compared to all other substrates (1.67:1 to 2.97:1). Chicken cartilage was rapidly fermentable, indicated by a greater maximal rate of gas production (R_max) compared with all other substrates (P < 0.05). In general, animal substrates showed an earlier occurrence for maximal gas production rate compared to FOS. Rabbit hair, skin, and bone were poorly fermentable substrates, indicated by the least amount of OMCV and total SCFA among animal substrates (P < 0.05). The greatest amount of ammonia production among animal substrates was measured after incubation of collagen and rabbit bone (P < 0.05). This study provides the first insight into the potential of animal tissues to influence large intestinal fermentation in a strict carnivore, and indicates that animal tissues have potentially similar functions as soluble or insoluble plant fibers in vitro. Further research is warranted to assess the impact of fermentation of each type of animal tissue on gastro-intestinal function and health in the cheetah and other felid species.

In chickens, thymic CD4⁺CD25⁺ cells are characterized as regulatory T cells. The objectives of this experiment were to study the effects of an in vivo lipopolysaccharide (LPS) injection on the percentage of CD4⁺CD25⁺ cells in peripheral organs and the suppressive properties of splenic CD4⁺CD25⁺ cells in chickens. Chickens were injected with LPS and CD4⁺CD25⁺ cells were analyzed at 1, 2, 3, 5, and 10 d post LPS injection. The LPS injection increased CD4⁺CD25⁺ cell percentage approximately 5-fold in the blood at 1 d post LPS injection (P < 0.001), 3-fold in the thymus at 3 d post LPS injection (P = 0.001), and 2.5-fold in the spleen at 2 d post LPS injection (P = 0.001) compared to the no-LPS-injected group. The LPS injection did not alter the CD4⁺CD25⁺ cell percentage in the cecal tonsil (P = 0.162), lung (P = 0.098), or bone marrow (P = 0.071) at any time point measured. At 2 d post LPS injection, splenic CD4⁺CD25⁺ cells lost their suppressive ability (P < 0.001). At 5 d post LPS injection, splenic CD4⁺CD25⁺ cells not only regained their suppressive ability, but also became supersuppressive (P < 0.001). Splenic CD4⁺CD25⁺ cells at 5 d post LPS injection produced 5.5-fold more (P = 0.005) IL-10 mRNA than splenic CD4⁺CD25⁺ cells at 0 and 2 d post LPS injection. In conclusion, chicken regulatory T cells are differentially activated to facilitate immune response during the early stage of inflammation and to facilitate immune suppression at a later stage of inflammation.

Tryptophan as a precursor of serotonin (5-hydroxytryptamine, 5-HT) has long been used to extenuate aggressive behavior and control stress of humans as well as several farm animals. This study was conducted to determine the effect of supplemental L-Trp on growth, cerebral 5-HT concentration, stress hormone concentration, oxidative stress status, and behavior response of pigs under social stress, and also to determine an optimal daily total Trp intake that would benefit nursery pigs under social stress. Seventy two individually housed barrows at 6 wk of age were randomly allotted to 6 treatments with supplementation of 0, 2, 4, 6, 8, or 10 g L-Trp/kg to a corn and soybean meal based diet. Pigs were fed assigned diets for 15 d. Body weight was measured on d 0, 5, 10, and 15. Saliva and blood were collected on d 5, 10, and 15. On d 5 and 10, all 12 pigs in each treatment were paired in 6 new pens to record behavior for a 2-d period and returned to original individual pens. On d 15, pigs were euthanized to obtain hypothalamus. During the first 5 d, ADG and G:F increased (linear, P < 0.01) with increasing supplemental L-Trp. During the entire 15 d, ADG and G:F increased (linear, P = 0.01 and P < 0.01, respectively) with increasing supplemental L-Trp. Estimates of the daily total Trp intake based on ADG on d 15 were 10.8 g/d (P < 0.01; R² = 0.16) using a one-slope broken-line analysis. Hypothalamic 5-HT and 5-hydroxyindoleacetic acid increased (linear, P < 0.01 and P = 0.03, respectively) with increasing supplemental L-Trp. Malonedialdehyde in plasma and hypothalamus, as well as salivary cortisol, on d 15 decreased (linear, P = 0.01, P < 0.01, and P < 0.01, respectively) with increasing supplemental L-Trp. Plasma urea nitrogen decreased (linear, P < 0.01) with increasing supplemental L-Trp. Increasing supplemental L-Trp affected pig behaviors during the first 2-d observation period by decreasing (quadratic, P = 0.04) lying, decreasing (linear, P = 0.04) sitting, and increasing (linear, P = 0.02) drinking. Overall, supplementation of L-Trp improved growth performance of 6 wk-old nursery pigs under social stress in association with increasing hypothalamic 5-HT production, reducing stress hormone concentrations, decreasing lipid peroxidation, increasing drinking, and reducing sitting and lying. Increase in BW gain of nursery pigs under social stress was maximal when daily total Trp intake was 10.8 g.

Two feedlot studies were conducted to investigate the timing and duration of supplemental vitamin A withdrawal from feedlot cattle diets to reduce intramuscular adipose tissue vitamin A concentration and improve carcass quality. In Exp. 1, Angus crossbred steers (n = 84, BW = 211 ± 4 kg) were allotted to 4 treatments: no supplemental vitamin A for 227 d, no supplemental vitamin A for 112 d followed by 115 d of supplemental vitamin A, supplemental vitamin A for 112 followed by no supplemental vitamin A for 115 d, or supplemental vitamin A for 227 d. In Exp. 2, Angus crossbred steers (n = 80, BW = 210 ± 5 kg) were allotted to 4 treatments: early weaning with or without supplemental vitamin A, and traditional weaning with or without supplemental vitamin A. In both experiments, serum vitamin A concentrations were greatest (P < 0.05) 56 d after cattle were weaned and placed in the feedlot, regardless of feedlot dietary vitamin A concentration. Hepatic vitamin A stores were dramatically decreased (P < 0.05) in the first 56 d and remained depressed as long as steers were not supplemented with vitamin A. At the end of the finishing period, vitamin A concentrations were less in intramuscular than subcutaneous adipose tissue. Growth was not affected by finishing cattle without supplemental dietary vitamin A (P > 0.10). Dietary vitamin A supplementation did not affect USDA Yield grades. However, in Exp. 2, cattle without supplemental vitamin A had greater (P < 0.001) ether extractable lipid in the LM. Ether extractable lipid in the LM or marbling scores were enhanced when intramuscular adipose tissue vitamin A concentration was reduced in response to feeding diets without supplemental vitamin A.

This study examined the impact of a single dose of azaperone administered to sows at the end of farrowing on piglet weight gain and mortality during the lactation period. Two hundred and fifty two sows (JSR hybrid) housed in a conventional farrowing crate system were assigned to either a treatment or a control group. The sow’s parities were between one and six. The differences between live birth weight and weight at weaning were recorded for 3,093 individual piglets. Serum concentrations of IgG of 485 piglets also were recorded during tail docking. Median and interquartile range (IQR) were 5.1 (2.9 to 9.5) mg·mL^-1 in the control group and 5.6 (3.1 to 12.1) mg·mL^-1 in the azaperone group (P > 0.05). Litter size was 13.0 (11 to 15) total born piglets and birth weight was 1.28 (1.05 to 1.52) kg. Weaning weight for the control group was 5.64 (4.73 to 6.54) kg compared to 5.78 (4.79 to 6.71) kg for the azaperone treated group (P = 0.005). Daily weight gain differed significantly (P = 0.001) between the two groups, 205 g for the controls, compared to 214 g for the azaperone group. There were no significant differences between piglet mortality rates (17% and 20%), respectively. Azaperone applications to sows tended to have a positive effect on productivity. Effect was greatest in the primiparous sows and declined with increasing parity. This may have been due to both physiological and behavioral differences between the sows as they experienced increasing numbers of gestations, farrowings and lactation periods.

A 2-yr grazing experiment was conducted with crossbred steers (8 to 10 mo and with initial BW of 304 kg ± 34 kg in 2008 and 277 kg ± 24 in 2009) to evaluate animal performance and pasture responses of a late maturing tall fescue [Lolium arundinaceum (Schreb.) Darbysh; KYFA9301] population infected with the AR584 novel, non-toxic endophyte (Neotyphodium coenophialum) (NE9301) as compared with Kentucky 31 fescue infected with the common toxic endophyte strain (KY31), ‘Jesup MaxQ’ fescue infected with the AR542 endophyte (MaxQ), and endophyte-free KYFA9301 (EF9301). Treatments were assigned for seeding in 1.0-ha pastures in a randomized complete block design with three replications. Pastures were grazed from 6 May to 23 July in 2008 (76 d) and 2 April to 25 June in 2009 (84 d). Each pasture was grazed with 4 tester steers and put-and-take steers were used to maintain forage mass at 2,500 ± 250 kg DM/ha. Shrunk BW was taken at initiation and termination of grazing each year. Rectal and skin temperatures were recorded and jugular blood was collected each year at approximately d 28, 56, and study completion. Forage samples were collected at 2-wk intervals for analyzing CP, IVDMD, ADF, and NDF. Responses were analyzed with mixed models and preplanned orthogonal contrasts were used to compare KY31 with non-toxic fescues, EF9301 vs. novel endophyte fescues, and NE9301 vs. MaxQ. All steer responses were similar (P > 0.10) among the non-toxic fescues. Average daily gains and total BW gain/ha for the 3 non-toxic fescues were greater (P < 0.001) than for KY31. Rectal/skin temperatures for the 3 non-toxic fescues were less (P < 0.001) and serum prolactin concentrations were greater (P < 0.01) than for KY-31. Pasture carrying capacity was greater (P = 0.003) for KY31 than the 3 non-toxic fescues, and was greater for EF9301 (P = 0.017) than the 2 novel endophyte fescues. However, stocking rates (kg BW/ha) at the initial and midpoint days of grazing were similar (P > 0.40) among endophyte-fescue combinations, but by the end of the grazing season stocking rate was greater (P < 0.001) for KY31 than for the non-toxic fescues and was greater (P = 0.053) for NE9301 than for MaxQ. Results indicated that NE9301 is as effective as EF9301 and MaxQ in improving weight gain and alleviating fescue toxicosis, and that NE9301 can provide higher carrying capacities than MaxQ in late June and July.

The pork supply chain values steady and undisturbed piglet production. Fertilization and maintaining gestation in warm and hot climates is a challenge that can be potentially improved by selection. The objective of this study was to estimate 1) genetic variation for farrowing rate of sows in two dam lines and their reciprocal cross; 2) genetic variation for farrowing rate’s heat tolerance, which can be defined as the random regression slope of farrowing rate against increasing temperature at day of insemination, and the genetic correlation between farrowing rate and heat tolerance; 3) genetic correlation between farrowing rate in purebreds and crossbreds; and 4) genetic correlation between heat tolerance in purebreds and crossbreds. The estimates were based on 93,969 first insemination records per cycle, from 24,456 sows inseminated between January 2003 and July 2008. These sows originated from a Dutch purebred Yorkshire dam line (D), an International purebred Large White dam line (I), and from their reciprocal crosses (C) raised in Spain and Portugal. Within-line and crossbred models were used for variance component estimation. Heritability estimates for farrowing rate were 0.06, 0.07, and 0.02 using within-line models for D, I, and C, respectively, and 0.07, 0.07, and 0.10 using the crossbred model, respectively. For farrowing rate, purebred-crossbred genetic correlations were 0.57 between D and C and 0.50 between I and C. When including heat tolerance in the within-line model, heritability estimates for farrowing rate were 0.05, 0.08, and 0.03 for D, I, and C, respectively. Heritability for heat tolerance at 29.3°C was 0.04, 0.02, and 0.05 for D, I, and C, respectively. Genetic correlations between farrowing rate and heat tolerance tended to be negative in crossbreds and I-line sows, implying selection for high levels of production traits, such as growth- and reproductive output, is likely to increase environmental sensitivity. This study shows that genetic selection for farrowing rate and heat tolerance is possible. However, when this selection is solely based on purebred information the expected genetic progress on farrowing rate and heat tolerance in crossbreds (commercial animals) would be inconsequential.

Maternal nutrient restriction leads to alteration in fetal adipose tissue and offspring from obese mothers have an increased risk of developing obesity. We hypothesized that maternal obesity increases fetal adipogenesis. Multiparous ewes (Columbia/Rambouillet cross 3 to 5 yr of age) carrying twins were assigned to a diet of 100% (Control; CON; n = 4) or 150% (Obese; OB, n = 7) of NRC maintenance requirements from 60 d before conception until necropsy on d 135 of gestation. Maternal and fetal plasma were collected and stored at -80ºC for glucose and hormone analyses. Fetal measurements were made at necropsy, and perirenal, pericardial, and subcutaneous adipose tissues were collected from 7 male twin fetuses per group and snap frozen at -80ºC. Protein and mRNA expression of fatty acid translocase (cluster of differentiation [CD] 36), fatty acid transport proteins (FATP) 1 and 4, insulin-sensitive glucose transporter (GLUT-4), fatty acid synthase (FASN), and acetyl-coA carboxylase (ACC) was evaluated. Fetal weight was similar but fetal carcass weight (FCW) was reduced (P < 0.05) in OB versus CON fetuses. Pericardial and perirenal adipose tissue weights were increased (P < 0.05) as a percentage of FCW in OB versus CON fetuses, as was subcutaneous fat thickness (P < 0.001). Average adipocyte diameter was greater (P < 0.01) in the perirenal fat and the pericardial fat (P = 0.06) in OB fetuses compared to CON fetuses. Maternal plasma showed no difference (P > 0.05) in glucose or other hormones, fetal plasma glucose was similar (P = 0.42), and cortisol, IGF-1, and thyroxine were reduced (P ≤ 0.05) in OB fetuses compared to CON fetuses. Protein and mRNA expression of CD 36, FATP 1 and 4, and GLUT-4 were increased (P ≤ 0.05) in all fetal adipose depots in OB versus CON fetuses. The mRNA expression of FASN and ACC was increased (P < 0.05) in OB vs.CON fetuses in all 3 fetal adipose tissue depots. Fatty acid concentrations were increased (P = 0.01) in the perirenal depot of OB versus CON fetuses and specific fatty acid concentrations were altered (P < 0.05) in subcutaneous and pericardial adipose tissue due to maternal obesity. In conclusion, maternal obesity was associated with increased fetal adiposity, increased fatty acid and glucose transporters, and increased expression of enzymes mediating fatty acid biosynthesis in adipose depots. These alterations, if maintained into the postnatal period, could predispose the offspring to later obesity and metabolic disease.

The aim was to study relationships between morbidity, defined through prevalence of diseases of rabbit females, and BCS, and to assess the effect of several risk factors on both morbidity and BCS. Our study was based on individual examinations of 18,510 does in lactation, on 103 farms. We evaluated BCS on a linear scale from 1 to 9, 5 being the optimum. Prevalences of major diseases were: 22.7%, 4.0% and 6.4%, for coryza, mastitis and ulcerative pododermatitis, respectively. In addition, prevalence was 3.0% for diseases of minor presentation, including manges, which had a prevalence of 1.9%. BCS of the R line (selected for growth) was 5.55 ± 0.14, whereas for the A line (selected for litter size) it was 4.40 ± 0.11. Females with more than 20 kindlings had on average a BCS 0.25 ± 0.07 units less than those in the twelfth lactation (P = 0.0002). Optimal BCS 4.60 ± 0.11 was reached during the third lactation week. Sick females had a BCS of 0.6 ± 0.01 units lower than healthy females. Females with a footrest had on average a BCS 0.19 ± 0.05 units greater than those without. The absence of footrests was an enabling risk factor for ulcerative pododermatitis, the prevalence of which increased by 53%. Ulcerative pododermatitis was associated (P = 0.045) with diet; females consuming a rich energy diet were prone to having this disorder; 1 SD increase in DE (0.32 MJ) determined an increase in ulcerative pododermatitis prevalence of 0.8 percentage points. Diet was not an enabling risk factor for the other diseases. The genetic type to which a female belongs is a predisposing risk factor of disease; P, V and H were also maternal lines, while S group was exclusively formed by maternal lines. With regard to coryza, the S group had the greatest prevalence (44.0%), followed by A, P, R (19.0 to 21.0%); the V line, selected for prolificacy, showed the lowest prevalence (12.0%). For the case of mastitis although significant (P < 0.05), the magnitude of the differences between disease prevalence was lower; R line had a mastitis prevalence of 11.0% while the lowest prevalence was observed for V does (4.0%). Simultaneous evaluation of both BCS and morbidity on the rabbit farm is recommended for the right assessment of welfare conditions. In this study, the relationships between them have been shown, as well as how other intrinsic and extrinsic risk factors modulate them; all these factors should be considered during a welfare assessment.

Cattle genetically selected for twin ovulations and births (Twinner) exhibit increased ovarian follicular development, increased ovulation rate, and greater blood and follicular fluid IGF-1 concentrations compared with contemporary cattle not selected for twins (Control). Experimental objectives were to: 1) assess relationships among aromatase (CYP19A1), IGF-1 (IGF1), IGF-2 receptor (IGF2R), and FSH receptor (FSHR) mRNA expression in small (≤ 5 mm) antral follicles, and 2) determine their association with increased numbers of developing follicles in ovaries of Twinner females. Ovaries were collected from mature, cyclic (d 3 to 6) Twinner (n = 11) and Control (n = 12) cows at slaughter and pieces of cortical tissue were fixed and embedded in paraffin. Expression of mRNA was evaluated by in situ hybridization using ³⁵S-UTP-labeled antisense and sense probes for CYP19A1, FSHR, IGF1, and IGF2R mRNA. Silver grain density was quantified within the granulosa and theca cells of individual follicles (2 to 7 follicles/cow) by Bioquant image analysis. Follicles of Twinners tended to be smaller in diameter than Controls (1.9 + 0.1 vs. 2.3 + 0.1 mm; P = 0.08), but thickness of granulosa layer did not differ (P > 0.1) by genotype. Relative abundance of CYP19A1 (P < 0.01) and FSHR (P < 0.05) mRNA was greater in granulosa cells of Twinners vs. Controls, respectively; whereas, IGF2R mRNA expression was less in both granulosa (P < 0.01) and theca (P < 0.05) cells in follicles of Twinners vs. Controls, respectively. Abundance of CYP19A1 mRNA in granulosa cells was correlated negatively with IGF2R mRNA expression in both granulosa (r = -0.33; P < 0.01) and theca (r = -0.21; P = 0.05) cells. Expression of IGF1 mRNA was primarily in granulosa cells, including cumulus cells, and its expression did not differ between Twinners vs. Controls (P > 0.10). Detected increases in CYP19A1 and FSHR, but not IGF1, mRNA expression along with decreases in IGF2R mRNA expression in individual follicles of Twinners support the hypothesis that increased follicular development and steroidogenesis in Twinner females result from increased extra-ovarian IGF-1 production. Furthermore, a reduction in follicular IGF2R mRNA expression accompanied by a reduction in receptor numbers would increase availability of free IGF-2 and its stimulation of follicular development in Twinners.

This study describes a method for discriminating Rangifer antlers from true Cervus antlers using agarose gel electrophoresis, capillary electrophoresis, quantitative real-time PCR, and allelic discrimination. Specific primers labeled with fluorescent tags were designed to amplify fragments from the mitochondrial D-loop genes for various Cervus subspecies and Rangifer tarandus differentially. A 466 bp fragment that was observed for both Cervus and Rangifer antlers served as a positive control, while a 270 bp fragment was specifically amplified only from Rangifer antlers. Allelic discrimination was used to differentiate between Cervus and Rangifer antlers, based on the amplification of specific alleles for both types of antlers. These PCR-based assays can be used for forensic and quantitative analyses of Cervus and Rangifer antlers in a single step, without having to obtain any sequence information. In addition, multiple PCR-based assays are more accurate and reproducible than a single assay for species-specific analysis, and are especially useful in this study for the identification of original Cervus deer products from fraudulent Rangifer antlers.

An experiment was conducted to evaluate the effects of dietary lactose alone or in combination with a yeast-dried milk product (50% dried near-dated milk; 50% dried yeast) on growth performance, fecal microbiota, and immune status in nursery pigs. A total of 108 pigs (age, 20 ± 1 d; initial BW, 6.07 ± 0.03 kg) were randomly allotted to 18 pens (6 pigs/pen; 6 pens/treatment). Dietary treatments were: 1) control, 2) control + lactose, and 3) control + lactose + 5% yeast-dried milk. Except for the control diet, diets in Phase 1 (wk 1 and 2), 2 (wk 3 and 4), and 3 (wk 5) contained 20, 15, and 5% total lactose, respectively. Blood samples were collected from all pigs at d 0, 14, 28, and 35 to determine circulating IgG, IgA, and tumor necrosis factor (TNF)-α concentrations. At d 0, 7, and 14, fecal samples were collected (n = 18; 6 pigs/treatment) to evaluate fecal microbiota using PCR-denaturing gradient gel electrophoresis. Compared to pigs fed the control diet, pigs fed lactose and lactose with yeast-dried milk had greater (P < 0.05) ADG and tended (P = 0.07) to have greater BW and ADFI during Phase 1. There were no differences for BW, ADG, or ADFI during Phase 2, 3, or the overall experimental period. A main effect of treatment was observed for circulating IgA where control pigs had greater (P < 0.01) IgA compared to pigs fed lactose with or without yeast-dried milk; however, no effects of treatment were observed for circulating IgG or TNF-α. No differences in microbial diversity indices were observed on d 7 or 14 among treatments. However, a shift in microbial composition was observed on d 7 with lactose-fed pigs having greater (P < 0.05) putative L. johnsonii staining intensity compared to control pigs and pigs fed lactose plus yeast-dried milk. On d 14, L. reuteri tended (P = 0.15) to be enhanced, and L. delbrueckii was eliminated (P < 0.04) by feeding lactose with or without yeast-dried milk. This research indicates that growth performance, immune status, and fecal microbiota are affected by dietary inclusion of lactose alone, or in combination with yeast-dried milk.

The objective of this study was to compare performance, physiological, and reproductive responses of beef heifers consuming forages differing in nutritional quality and offered a low-starch energy supplement at 2 different frequencies. Forty-eight Brahman x British heifers (initial age = 294 ± 3 d) were allocated into 1 of 16 drylot pens (3 heifers/pen) which were randomly assigned to receive, in a 2 x 2 factorial arrangement: (1) low-quality hay [LQ; stargrass (Cynodon nlemfuensis) with 8% CP and 81% NDF, DM basis] and daily supplementation (S7); (2) LQ and supplementation 3 times weekly (S3); (3) medium-quality hay [MQ; bermudagrass (C. dactylon) with 12% CP and 74% NDF, DM basis] and S7; (4) MQ and S3. Throughout the study (d 0 to 120), hay was offered in amounts to ensure ad libitum access, and a supplement based on soybean hulls and wheat middlings was offered at weekly rates of 15.8 and 7.9 kg/heifer (DM basis) for LQ and MQ, respectively. Forage and total DMI were evaluated daily, from d 20 to 26, d 34 to 40, and d 48 to 54. Blood samples were collected weekly for determination of plasma progesterone to evaluate puberty attainment. Blood samples were also collected daily, from d 13 to 16, d 27 to 30, d 41 to 44, and d 55 to 58 for determination of plasma urea nitrogen (PUN), glucose, insulin, IGF-1 and NEFA. On d 60, heifers were reallocated by treatment into 4 paddocks and exposed to Angus bulls (1:12 bull:heifer ratio) until d 120. Date of conception was estimated retrospectively by subtracting gestation length (286 d) from the calving date. Heifers receiving S7 had similar (P = 0.52) ADG compared with S3 heifers (0.27 vs. 0.25 kg/d). Heifers provided S7 had less daily variation in hay DMI and plasma concentrations of glucose, NEFA, and IGF-I compared with S3 cohorts (supplementation frequency x day interaction; P < 0.01). Similarly, heifers offered MQ and LQ and receiving S7 had less daily variation in total DMI, energy and protein intake, and plasma concentrations of PUN compared with heifers offered MQ and LQ and receiving S3 (hay quality x supplementation frequency x day interaction; P < 0.01). Attainment of puberty and pregnancy were hastened in S7 heifers compared with S3 heifers (supplementation frequency x week interaction; P < 0.02). Therefore, reproductive development of beef replacement heifers consuming diets based on low- and medium-quality forages are enhanced when low-starch energy supplements are offered daily instead of 3 times weekly.

The objectives were to investigate if partial substitution of a grazing diet with a supplemental high-starch feed during the last 12 d of gestation improved colostrum yield and neonatal activity in does grazing semi-arid rangeland. For the first objective, 25 pregnant does were randomly assigned to 1 of 2 treatments: (1) grazing only (control; n = 11), and (2) grazing plus 0.6 kg/d of supplemental corn (as fed), a high starch feed, during the last 12 ± 1.0 d before parturition (SC; n = 14). Colostrum was collected at parturition and again at 1, 3, 6, and 10 h postpartum for yield and composition. In all goats, blood concentrations of glucose and plasma progesterone were determined. Total colostrum yield/10 h was greater (P = 0.002) in the SC does (1,102 ± 144 g) than in control does (405 ± 50 g). From 6 to 10 h postpartum, contents of colostrum protein and solids not fat were lower (P ≤ 0.012) whereas lactose contents were greater (P = 0.035) in the SC does than in control does. Concentration of glucose in the blood at parturition was greater (P = 0.037) in the SC does (160 ± 13 mg/dL) than in control does (115 ± 12 mg/dL). A significant decrease in plasma progesterone concentrations occurred 1 d before parturition in control does, whereas the decrease occurred 3 d before parturition in SC does. For the second objective, 20 does (10 per group) and their single kids were randomly assigned to the same treatments as above for evaluation of dietary treatment on neonatal activity. Kid activity was assessed using videos recorded during the first 90 min after birth. Frequency of low-pitched bleats was greater (P< 0.001) in kids of SC does than in kids of controls. Frequencies and durations of teat seeking from 30 to 90 min after birth and of suckling activity were greater (P ≤ 0.015) in kids of SC does than in kids of controls. Duration of parturition was longer (P = 0.001) in control does (58 ± 10.2 min) than in SC does (21 ± 2.8 min). Finally, percentage of fetal malpresentation was greater (P = 0.036) in control does (33.3%) than in SC does (9.0%). We conclude that partial substitution of the grazing diet with a high-starch feed, corn, during the last 12 d of gestation improved colostrum yield and neonatal activity in goats grazing subtropical semi-arid rangeland.

It was hypothesized that a high-concentrate diet fed during early calfhood alters the expression of genes within the arcuate nucleus that subserve reproductive competence. Beef heifers (n = 12) were weaned at approximately 3 mo of age, and following acclimation, were allocated randomly to 1 of 2 nutritional groups: 1) High Concentrate/High Gain (HC/HG); high concentrate diet fed to promote a gain of 0.91 kg/d, or 2) High Forage/Low Gain (HF/LG); forage-based diet fed to promote a gain of 0.45kg/d. Experimental diets were fed under controlled intake for 91 d. At the end of 91 d, heifers were slaughtered by humane procedures, blood samples were collected, brains were removed, liver weights were determined, and rumen fluid was collected for VFA analyses. Tissue blocks containing the hypothalamus were dissected from the brains, frozen, and cut using a cryostat, and frozen sections were mounted on slides. Tissue from the arcuate nucleus (ARC) was dissected from sections for mRNA extraction. Microarray analysis was used to assess genome-wide transcription in the ARC using a 60-mer oligonucleotide 44K bovine expression array. The ADG was greater (P < 0.001) in heifers fed the HC/HG diet than in heifers fed the HF/LG diet. At slaughter, mean propionate to acetate ratio in the ruminal fluid and liver weight as a percentage of BW were increased (P < 0.005) in HC/HG compared to HF/LG heifers. Mean serum concentrations of insulin (P < 0.05) and IGF-1 (P < 0.005) were greater, and leptin tended to be greater (P = 0.1) in HCHG heifers compared to HF/LG heifers. Approximately 345 genes were observed to be differentially expressed in the HC/HG group with approximately 2/3 of the genes exhibiting increased expression in the HC/HG group. Genes exhibiting decreased expression in the HC/HG group included AGRP and NPY, products of which are known to regulate feed intake and energy expenditure. Functional annotation of enriched Gene Ontology terms indicates that a number of biological processes within the hypothalamus are affected by consumption of high-concentrate diets, including those related to control of feed intake, regulation of cellular metabolic processes, receptor and intracellular signaling, and neuronal communication. In summary, dietary treatments shown previously to accelerate the timing of pubertal onset in heifers increased ruminal propionate, promoted enhanced metabolic hormone secretion, and altered gene expression in the arcuate nucleus.

In commercial pigs, the greatest susceptibility for pre-weaning mortality occurs in low birth-weight piglets. Despite their overall decreased birth weight, Meishan (MS) piglets have lower pre-weaning mortality rates compared with contemporary Western breeds. The objective of the current study was to determine the contributions of the maternal uterine environment, piglet genotype, and their interaction on the development of neonatal piglets pertaining to pre-weaning survivability using reciprocal embryo transfer between MS and White crossbred (WC) pigs. Twenty-five successful pregnancies were produced from 2 farrowing seasons, generating litters of maternal uterine environment (ME) by piglet genotype (PG) combinations; MS x MS (n = 4 litters), MS x WC (n = 7 litters), WC x MS (n = 7 litters), and WC x WC (n = 7 litters). At approximately 24 h of age (d 1), piglets (n = 173) were weighed and a blood sample was taken. Hematocrit, hemoglobin, glucose, plasma urea nitrogen, albumin, NEFA, lactate, and cortisol were measured in all blood samples. Representative piglets (n = 46) from each litter were harvested and body measurements (i.e., organ weights, tissue glycogen content, and body composition) were determined. Piglet data were analyzed by ANOVA using MIXED model procedures. Both ME (P < 0.001) and PG (P < 0.01) affected piglet BW, illustrating that piglets gestated in WC gilts were heavier than piglets gestated in MS gilts, and WC piglets were heavier than MS piglets. Serum albumin levels were increased (P < 0.05) in MS piglets compared with WC piglets, indicating greater liver maturity. Significant ME x PG interactions were observed for hematocrit and hemoglobin in which the greatest levels were observed in MS piglets gestated in MS and WC gilts and the lowest levels were observed in WC piglets gestated in WC gilts, demonstrating increased oxygen carrying capability. The percentage of fat and nitrogen, as well as the gross energy of the body, were greater (P < 0.05) in MS piglets, indicating greater energy stores. Liver, bicep femoris, and longissimus dorsi glycogen concentrations were greater (P < 0.01) in WC piglets compared with MS piglets, demonstrating increased glycogen catabolism in MS piglets. This study demonstrated limited interactions between the maternal uterine environment and piglet genotype on weaning survivability potential, suggesting that the MS piglet is a viable model for pre-weaning survivability.

Intramuscular fat (IMF) in cattle is an important component of traits that influence meat quality. We measured carcass characteristics and gene expression levels in Korean steers to clarify the molecular mechanism(s) underlying IMF deposition in musculus longissimus dorsi (LM) tissue by determining the correlation between IMF content and gene expression levels and by developing models to predict IMF content using gene expression levels. IMF deposition is determined by a balance between fat deposition and fat removal in the LM. We measured mRNA levels of lipid metabolic genes including lipogenesis [acetyl CoA carboxylase (ACC), fatty acid synthase (FASN)], fatty lipid uptake [lipoprotein lipase (LPL), fatty acid translocase (CD36), fatty acid transport protein 1 (FATP1)], fatty acid esterification [glycerol-3-phosphate acyltransferase 1 (GPAT1), acylglycerol phosphate acyltransferase 1 (AGPAT1), diacylglycerol acyltransferase 1 (DGAT1), DGAT2], lipolysis [adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), monoglyceride lipase (MGL)], and fatty acid oxidation [carnitine palmitoyl transferase 1B, very long-chain acyl-CoA dehydrogenase (VLCAD), medium-chain acyl-CoA dehydrogenase (MCAD)] in the LM. The mRNA levels of the GPAT1 gene showed the highest correlation (r = 0.74; P < 0.001) with IMF content among nine fat deposition genes. The gene expression levels of other fat deposition genes including ACC, FASN, LPL, CD36, FATP1, AGPAT1, DGAT1, and DGAT2 also exhibited significant positive correlations (P < 0.05) with IMF content in the LM. Conversely, ATGL mRNA levels showed the highest negative correlation (r = –0.68; P < 0.001) with IMF content in the LM among five fat removal genes. The expression of other fat removal genes including MGL, VLCAD, and MCAD showed significant negative correlations (P < 0.05) with IMF content. Our findings show that the combined effects of increases in lipogenesis, fatty acid uptake, fatty acid esterification, and of decreases in lipolysis and fatty acid oxidation contribute to increasing IMF deposition in Korean steers. The multiple regression analysis revealed that the mRNA level of the GPAT1 gene in the LM was the first major variable predicting IMF content (54%) among 15 lipid metabolic genes. The second was mRNA levels of ATGL (11%). In conclusion, these results suggest that GPAT1 and ATGL genes could be used as genetic markers to predict IMF deposition in the LM.

Surgical castration is a common management practice performed on male pigs to prevent the occurrence of boar taint. Surgical castration is known to cause physiological and behavioral changes in pigs indicative of pain-induced distress; however, it is commonly performed without pain relief. The objective of this study was to evaluate the effectiveness of carbon dioxide gas (CO₂) anesthesia and a non-steroidal anti-inflammatory drug (NSAID) to alleviate the pain caused by castration. At 3 d of age, male pigs were either control handled (CON), castrated without pain relief (CAS), given an NSAID and then immediately castrated (CAS+NSAID), anesthetized with CO₂ and then castrated (CAS+CO2), or anesthetized with CO₂ and given an NSAID at the time of castration (CAS+BOTH). Blood samples were collected prior to castration, and at 30, 60, 120, and 180 min, 24 h, and 3 d after castration or handling for analysis of cortisol, C-Reactive protein (CRP), and substance-P (SP) concentrations. This study was then repeated using the same treatment groups, and the behavioral response to castration and handling were measured using a 1-min scan sampling procedure. The percentage of stress vocalizations was recorded during the administration of all treatments. Anesthesia and analgesia did not effectively reduce (P > 0.05) the cortisol response to surgical castration. Overall, CRP concentrations were greater (P < 0.07) in CAS and CAS+CO2 pigs as compared to CON and CAS+BOTH pigs. Sixty minutes after castration or handling, SP concentrations were greater (P < 0.08) in pigs given CO₂ anesthesia (CO2, CAS+CO2, and CAS+BOTH) than CON, CAS, and CAS+NSAID pigs. Pigs castrated without pain relief spent more (P < 0.001) time lying-without contact than all other treatments during the first 30 min after castration, but thereafter CAS+CO2 pigs spent more (P < 0.001) time lying without contact than other treatments. During the first 30 min after the treatments were applied, CAS+CO2 pigs spent more (P < 0.01) time displaying pain-like behaviors than CON, CAS, CAS+NSAID, and CAS+BOTH pigs. The percentage of stress vocalizations was greater (P < 0.05) in CAS and CAS+NSAID pigs than all other treatments. Neither CO₂ anesthesia nor a NSAID, given separately or combined, markedly reduced the pain-induced distress caused by castration in pigs. More research is needed to evaluate practical methods of on-farm pain relief for pigs.

Polymorphisms in mitochondrial DNA (mtDNA) protein- and tRNA- coding genes were shown to be associated with various diseases in humans as well as with production and reproduction traits in livestock. Alignment of full length mitochondria sequences from the 5 known ovine haplogroups: HA (n=3), HB (n=5), HC (n=3), HD (n=2) and HE (n=2), (GenBank accession nos. HE577847-50, and 11 published complete ovine mitochondria sequences) revealed sequence variation in 10 out of the 13 protein coding mtDNA sequences. Twenty six of the 245 variable sites found in the protein coding sequences represent non-synonymous mutations. Sequence variation was observed also in 8 out of the 22 tRNAs mtDNA sequences. Based on the mtDNA control region and cytochrome B partial sequences along with information on maternal lineages within an Afec-Assaf flock, 1,126 Afec Assaf ewes were assigned to mitochondrial haplogroups HA, HB and HC, with frequencies of 0.43, 0.43 and 0.14, respectively. Analysis of birth weight and growth rate records of lamb (n=1286) and productivity from 4,993 lambing records revealed no associations between mitochondrial haplogroup affiliation and female longevity, lambs perinatal survival rate, lambs' birth weight and lambs' daily growth rate up to 150 d that averaged 1,664 d, 0.883, 4.5 kg and 320g/d, respectively. However, significant (P < 0.0001) differences among the haplogroups were found for ewes' prolificacy, with prolificacies (mean±SE) of 2.14±0.04, 2.25±0.04 and 2.30±0.06 lamb born/ewe lambing for the HA, HB and the HC haplogroups, respectively. Our results highlight the ovine mitogenome genetic variation in protein- and tRNA- coding genes, and suggest that sequence variation in ovine mtDNA is associated with variation in ewes' prolificacy.

Weight loss during transport or shrink (SHK) is a common occurrence in feeder cattle that results from a physiological, complex process. Previous studies have assessed the effects of environmental and dietary stressors on transport-associated weight loss; however, data on associations between shrink and subsequent health and performance parameters in feeder cattle are limited. Operational data from 13 U.S. commercial feedlots (n = 16,590 cattle cohorts) were used to quantify how SHK was associated with bovine respiratory disease (BRD) morbidity and overall mortality risks, HCW and ADG in feeder cattle cohorts arriving to feedlots during 2000 to 2008. Multivariable mixed-effects negative binomial and linear regression models were employed to determine these associations while accounting for other cohort-level demographic variables. The median SHK among the study cohorts was 3.0% with a mean (± SEM) of 2.4 ± 0.02%. The mean (± SEM) cumulative BRD morbidity was 10.0% ± 0.09% (median = 5.8%; range 0 to 100%) and the mean (± SEM) overall cumulative mortality was 1.3% ± 0.01% (median = 0.9%; range: 0 to 25.6%). The mean and median number of days on feed of cohorts experiencing initial BRD cases was 143 and 150 d (range = 23 to 288 d). The effects of SHK were significantly (P < 0.05) associated with BRD morbidity, overall mortality, HCW and ADG, and these effects were significantly (P < 0.05) modified by gender, season and mean arrival weight of the cohort. Combining data on weight loss during transport with cohort demographics could allow a more precise prediction of health and performance of feedlot cattle.

Most beef cattle are transported at least once during their lives and this potentially stressful practice may impact subsequent health and performance. Limited research is available quantifying the effects of transport on feedlot performance and health, and particularly the risk of bovine respiratory disease complex (BRD), which is the most common disease of weaned calves after arrival to the feedlot. The objective of this retrospective study was to determine potential associations between distance traveled (DTV) during transportation with health (cumulative BRD morbidity and mortality of all causes) and performance (ADG and HCW) parameters in cattle cohorts (n = 14,601) that arrived to 21 U.S. commercial feedlots from 1997 to 2009. Multivariable mixed-effects negative binomial and linear regression models were employed to determine associations between health and performance outcomes with DTV and other cohort-level demographic variables. Cattle were transported a median of 552 km from origin to feedlot with a mean (± SEM) of 698 ± 4.4 km. The mean (± SEM) cumulative BRD morbidity was 4.9% ± 0.01% (median = 1.1%; range: 0 to 100%) whereas the mean (± SEM) cumulative mortality due to all causes was 1.3% ± 0.01% (median = 0.8%; range: 0 to 28.7%). Distance traveled was significantly associated (P < 0.05) with BRD morbidity, overall mortality, HCW and ADG, and its effects were modified by demographic characteristics (i.e., cohort’s region of origin, mean arrival weight, gender, and the season of the year) of the cohort. Knowledge of the distance traveled during transportation could allow a more precise prediction of cattle feedlot health and performance.

The objective was to compare the acute-phase response of steers receiving different doses of bovine corticotropin-releasing hormone (CRH). Fourteen weaned Angus steers (BW = 191 ± 2.1 kg, age = 167 ± 4.7 d) fitted with an indwelling jugular catheter and a rectal temperature (RT) monitoring device were assigned to receive 1 of 3 treatments (i.v.): 1) 0.1 μg of CRH/kg of BW (CRH1; n = 5), 2) 0.5 μg of CRH/kg of BW (CRH5; n = 5), and 3) 10 mL of saline (0.9%; n = 4). Blood samples were collected via catheters, relative to treatment infusion (0 h), hourly from –2 to 0 h and 4 to 8 h, and every 30 min from 0 to 4 h. Rectal temperatures were recorded every 30 min from –2 to 8 h. Blood samples were also collected via jugular venipuncture and rectal temperatures assessed using a digital thermometer every 6 h from 12 to 72 h, and every 24 h from 96 to 168 h. All plasma samples collected during the study were analyzed for concentrations of haptoglobin. All plasma samples collected from –2 to 8 h were analyzed for cortisol concentrations. Serum samples collected hourly from -2 to 8 h were analyzed for concentrations of NEFA, IL-6, tumor necrosis factor (TNF)-α, and interferon-. Cortisol peaked at 0.5 h for CRH1 steers but returned to baseline levels at 1 h relative to infusion (time effect; P < 0.01). In CRH5 steers, cortisol peaked at 0.5 h and returned to baseline levels 3.5 h relative to infusion (time effect; P < 0.01). Cortisol concentrations did not change after treatment infusion for saline steers (time effect; P = 0.42). In CRH1 steers, NEFA concentrations peaked 5 h following treatment infusion (time effect; P = 0.01). Conversely, serum NEFA concentrations did not change for CRH5 and saline steers after treatment infusion (time effect; P > 0.37). Mean serum TNF-α concentrations in CRH1 steers after treatment infusion were greater compared with saline (P = 0.02), tended to be greater (P = 0.08) compared with CRH5, and were similar (P = 0.40) between CRH5 and saline steers. Mean RT in CRH1 steers after treatment infusion were greater (P < 0.04) compared with saline and CRH5, and similar (P = 0.50) between CRH5 and saline steers. Haptoglobin increased and peaked 72 h following treatment infusion for CRH1 steers (time effect; P = 0.01), but did not change for CRH5 and saline steers (time effect; P > 0.45). In conclusion, the bovine acute-phase response stimulated by CRH infusion is dependent on the CRH dose and the subsequent response in circulating cortisol.

The objective of the present study was to investigate culling guidelines for gilts and sows in Japanese commercial herds and to compare differences between culling guidelines and actual culling practices in different herd productivity groups. A questionnaire survey was undertaken to obtain information on culling guidelines in 115 commercial swine herds that participated in the PigCHAMP data-share program. The questionnaire included questions on guideline values for culling intervals and the number of conception failure occurrences that would trigger a culling decision to be made. Ninety-two of the 115 herds (80.0%) returned appropriate data for the study and were included in the present study. In addition to questionnaire data, culling data regarding the actual culling intervals and number of reservices for gilts and sows culled during 2007 to 2008 were also obtained for the same herds from a PigCHAMP database. Culled gilts and sows were divided into 4 female groups based on the stages of their reproductive life when they were culled: unmated gilts, mated gilts, unmated sows, and mated sows. Culling intervals in unmated gilts and sows were defined as the number of days from birth or weaning to culling, respectively, whereas in mated gilts and sows culling intervals were the number of days from last service to culling. Three herd productivity groups were formed on the basis of the upper and lower 25th percentiles of pigs weaned·mated female^-1·year^-1: high-, intermediate- or low-performing herds. For unmated gilts and sows actual culling intervals were 15 d shorter than the guideline culling intervals in the surveyed data submitted by producers (P < 0.05). This shorter actual culling period for unmated gilts and sows did not vary significantly between herd productivity groups in any parity. However, for mated gilts and sows the actual culling intervals were at least 30 d longer than the guideline culling intervals (P < 0.05). Guideline and actual culling intervals for mated gilts and sows were at least 10 d shorter in high-performing herds than in low-performing herds (P < 0.05). High-performing herds had lower proportions of sows culled after the second reservice than intermediate- or low-performing herds in parity groups 0 to 5 (P < 0.05). In conclusion, culling guidelines for mated sows differed between herd productivity groups, and culling guidelines for mated gilts and sows were not strictly followed in any herd group in the commercial herds.

The objective of this experiment was to examine the effect of castration technique on daily feed intake (DFI), daily water intake (DWI), growth performance, residual feed intake (RFI), and inflammatory response in weaned beef calves. Seventy-five beef calves (214 ± 3.2 kg; 200 ± 26 d of age) were housed in a GrowSafe 4000 feed intake facility 7 d post weaning (15 calves/pen). Calves were offered a total mixed ration (TDN = 67.3% and CP = 12.2%, DM = 89%) for ad libitum consumption. On d 0 calves were assigned to 1 of 5 treatments (n = 15 calves/treatment): 1) steers castrated surgically pre-weaning (52 d of age; CON); 2) intact bulls (BULL); 3) bulls castrated by the Callicrate Bander on d 0 (No-Bull Enterprises LLC, St. Francis, KS; BAN); 4) bulls castrated by the Henderson Castrating Tool on d 0 (Stone Mfg & Supply Co., Kansas City, MO; HEN) and 5) bulls castrated surgically utilizing an emasculator on d 0 (SUR). Average daily gain, DFI, and DWI were recorded over 84 d. Blood was collected from a sub-sample of calves (n = 45) on d 0, 2, 6, 9, 12, and 15 relative to castration. Castration decreased (P = 0.06) ADG for castrates compared to CON from d 0 to 14, but not d 0 to 84. Daily feed intake and DWI were similar (P > 0.10) among treatments during d 0 to 84. Gain:feed was not impacted by castration technique; however, RFI tended (P = 0.09) to be negative for CON and BULL compared to castrates on d 0 to 14 but not d 0 to 84. Acute phase protein analyses indicated that surgical castration (SUR or HEN) elicited a short-term inflammatory response in calves, whereas calves castrated with BAN elicited a delayed response. Calves castrated pre-weaning had improved d 0 to 14 ADG, feed intake, and inflammation response compared to calves castrated at weaning. Banding elicited a delayed negative response in ADG, DWI, and inflammation. In weaned calves, castration method did not impact performance, DFI, DWI, or inflammatory response during the 84 d trial.

The combined effects of probiotics (Lactobacillus acidophilus, Lactobacillus casei, Streptococcus faecium, and Saccharomyces cerevisae) and organic acids (sorbic and citric acid) on intestinal morphology and expression of immune-related genes were investigated. Day-old chicks were randomly assigned to 1 of 3 groups: birds not receiving probiotic or organic acids (control; T1), birds receiving an oral combination (1 g/L in water) of 10⁸ cfu/g of each of the aforementioned probiotics and organic acids for 7 (T2) or 14 d (T3). Each group was divided into 5 replicate pens of 20 birds each, and 5 birds from each group (1 from each pen) were sacrificed on d 11 and 22. Intestinal sections were collected for histological assessment, and reverse transcriptase polymerase chain reaction (RT-PCR) analysis was used to assess defensin and cathelicidins expression. Quantitative real-time PCR was used to assess toll-like receptors (TLR) and cytokine expression. Duodenal villus height was greater in T2 and T3 at d 11 (P ≤ 0.036) and 22 (P ≤ 0.015) compared to T1. At d 11, duodenal goblet cell/unit area was lower in T3, while it was greater in T2 compared to T1 in the jejunum (P = 0.009). Ileal goblet cell/unit area was greater in T3 at d22 compared to T1 (P < 0.001). Avian beta-defensin (AvBD)-3 was expressed in all tissues except the bursa of T3 birds at d 11, and TLR-2 was down regulated in the cecal tonsil of birds in T2 and T3 at d 11 compared to T1 (P = 0.020 and 0.003, respectively). Expression of IL-12p35 in the ileum at d 11 was down regulated in T2 and T3 compared to T1 (P = 0.030 and 0.012, respectively). Lower expression of INF- was observed in the ileum in T3 compared to T1 at d 11 (P = 0.047). Ileal IL-6 and IL-10 and cecal tonsil interferon-gamma (INF-) expressions were greater T2 at d 22 (P ≤ 0.047) than T1. In conclusion, supplementation of combined probiotics and organic acids resulted in inconsistent gut morphology associated responses, and avian beta-defensins and cathelicidins expression were not associated with combined probiotics and organic acids supplementation. Birds supplemented with combined probiotics and organic acids for 7 d showing similar responses in TLR-2, IL12p40, and IFN- compared to those supplemented for 14 d indicates that shorter periods of supplementation might be enough to elicit beneficial responses.

Beef cows in the subtropical USA must be adapted to the stressors of the environment, typically supplied by using Brahman breeding. Calves produced in the region, however, are usually grown and finished in more temperate regions, and have a perceived reputation for poor ADG and feed efficiency during finishing. Compromised fertility and carcass quality often associated with the Brahman have increased interest in tropically adapted Bos taurus breed types. The objective of this study was to evaluate three breeds [An=Angus(Bos taurus – temperate); Br=Brahman(B. indicus – tropical); and Ro=Romosinuano (B. taurus – tropical)] and all possible crosses during various segments of post-weaning growth, and for feed efficiency during the finishing phase. Steer calves (n = 473) born over three years were weaned in late September, backgrounded for at least 21 d (BKG), shipped 2,025 km to El Reno, OK in October, fed a preconditioning diet for 28 d (RCV), grazed wheat pasture from Nov. to May (WHT), finished on a conventional feedlot diet (FIN), and serially harvested after approximately 95, 125, and 150 d on feed. Body weight and ADG during each segment were tested using a mixed model that included calf age at weaning, year (Y), breed of sire (SB) and breed of dam (DB), and interactions. In addition, winter treatment (continuous wheat or reduced grazing of wheat with supplement) was included for the wheat and feedlot phases. Sire within SB x SB [and pen (barn x year) for feedlot phase] were considered random. The SB x DB interaction was significant for all traits (P < 0.01) except exit velocity taken at weaning and ADG during FIN, but both traits were affected by 3-way interactions with Y or harvest group. Tropically-adapted purebred steers had greater (P < 0.01) ADG than AnAn through weaning and BKG in FL but the reverse was true during the RCV and WHT segments. Similar, but less pronounced results were noted for F₁ steers with 100% tropical influence compared to those with only 50%. Heterosis was numerically greater for most traits for An x Br (11 to 64%) compared to An x Ro and Br x Ro (3 to 42%), which were similar. In a subset of the steers (n = 261), G:F was not influenced by level of tropical breeding, but tropically adapted steers were more efficient (P < 0.05) by residual feed intake. No heterosis was evident. These data show that in temperate zones, winter is the period when productivity of tropically adapted cattle is compromised.

Delphinium spp. contain numerous norditerpenoid alkaloids which are structurally delineated as 7, 8-methylenedioxylycoctonine (MDL) and N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids. The toxicity of many tall larkspur species has been primarily attributed to their high concentration of MSAL-type alkaloids, such as methyllycaconitine (MLA), which are typically 20 times more toxic than MDL-type alkaloids. However, the less toxic MDL-type alkaloids are often more abundant than MSAL-type alkaloids in most Delphinium barbeyi and Delphinium occidentale populations. Previous research demonstrated that MDL-type alkaloids increase the acute toxicity of MSAL-type alkaloids. In this study, we examined the role of MDL-type alkaloids on the overall toxicity of tall larkspur plants to cattle while controlling for the exact dose of MSAL-type alkaloids. Cattle were dosed with plant material from two different populations of tall larkspur containing either almost exclusively MDL- or MSAL-type alkaloids. These two plant populations were combined to create mixtures with ratios of 0.3:1, 1:1, 5:1, and 10:1 MDL- to MSAL-type alkaloids. The dose that elicited similar clinical signs of poisoning in mice and cattle was determined for each mixture based on the MSAL-type alkaloid content. As the ratio of MDL- to MSAL-type alkaloids increased, the amount of MSAL-type alkaloids required to elicit clinical signs decreased. These results indicate that the less toxic MDL-type alkaloids in tall larkspur exacerbate the toxicity of the MSAL-type alkaloids. Consequently, both the amount of MSAL-type alkaloids and the amount of total alkaloids should be fully characterized to more accurately determine the relative toxicity of tall larkspur plant material.

The objectives of this work were to assess alternative linear reaction norm (RN) models for genetic evaluation of Angus cattle in Brazil. That is, we investigated the interaction between genotypes and continuous descriptors of the environmental variation, to examine evidence of genotype by environment interaction (GxE) in post-weaning gain (PWG) and to compare the environmental sensitivity of national and imported Angus sires. Data were collected by the Brazilian Angus Improvement Program from 1974 to 2005 and consisted of 63,098 records and a pedigree file with 95,896 animals. Six models were implemented using Bayesian inference and compared using the Deviance Information Criterion (DIC). The simplest model was M₁, a traditional animal model, which showed the largest DIC and hence the poorest fit when compared to the 4 alternative RN specifications accounting for GxE. In M₂, a two-step procedure was implemented using the contemporary group posterior means of M₁ as the environmental gradient, ranging from -92.6 to +265.5 kg. Moreover, the benefits of jointly estimating all parameters in a one-step approach were demonstrated by M₃. Additionally, we extended M₃ to allow for residual heteroskedasticity using an exponential function (M₄) and the best fitting (smallest DIC) environmental classification model (M₅) specification. Finally, M₆ added just heteroskedastic residual variance to M₁. Heritabilities were lower at harsh environments and increased with the improvement of production conditions for all RN models. Rank correlations among genetic merit predictions obtained by M₁ and by the best fitting RN models M₃ (homoskedastic) and M₅ (heteroskedastic) at different environmental levels ranged from 0.79 and 0.81, suggesting biological importance of GxE in Brazilian Angus PWG. These results suggest that selection progress could be optimized by adopting environment specific genetic merit predictions. The PWG environmental sensitivity of imported North American origin bulls (0.046 ± 0.009) was significantly larger (P<0.05) than that of local sires (0.012 ± 0.013). Moreover, PWG of imported sires’ progeny exceeded that of native sires in medium and superior production levels. On the other hand, Angus cattle locally selected in Brazil tend to be more robust to environmental changes and hence be more suitable when production environments for potential progeny is uncertain.

The purpose of this study was to evaluate measures of boar taint as potential selection criteria to reduce boar taint so that castration of piglets will become unnecessary. Therefore, genetic parameters of boar taint measures and their genetic correlations with finishing traits were estimated. In particular, the usefulness of a human panel assessing boar taint (human nose score) was compared to chemical assessment of boar taint compounds, androstenone, skatole and indole. Heritability estimates for androstenone, skatole, indole were 0.54, 0.41, 0.33, respectively. The heritability for the human nose score using multiple panelists was 0.12, and ranged from 0.12 to 0.19 for individual panelists. Genetic correlations between scores of panelists were generally high up to unity. The genetic correlations between human nose scores and the boar taint compounds ranged from 0.64 to 0.999. The boar taint compounds and human nose scores had low or favorable genetic correlations with finishing traits. Selection index estimates indicated that the effectiveness of a breeding program based on human nose scores can be comparable to a breeding program based on the boar taint compounds themselves. Human nose scores can thus be used as a cheap and fast alternative for the costly determination of boar taint compounds, needed in breeding pigs without boar taint.

Endotoxin, also referred to as lipopolysaccharide (LPS), can stimulate localized or systemic inflammation via the activation of pattern recognition receptors. Additionally, endotoxin and inflammation can regulate intestinal epithelial function by altering integrity, nutrient transport and utilization. The gastrointestinal tract is a large reservoir of both Gram positive and negative bacteria, of which the Gram negative bacteria serve as a source of endotoxin. Luminal endotoxin can enter circulation via two routes: 1) nonspecific paracellular transport through epithelial cell tight junctions, and 2) via transcellular transport through lipid raft membrane domains involving receptor mediated endocytosis. Paracellular transport of endotoxin occurs through dissociation of tight junction protein complexes resulting in reduced intestinal barrier integrity, which can be a result of enteric disease, inflammation, or environmental and metabolic stress. Transcellular transport, via specialized membrane regions rich in glycolipids, sphingolipids, cholesterol, and saturated fatty acids, is a result of raft recruitment of endotoxin-related signaling proteins leading to endotoxin signaling and endocytosis. Both transport routes and sensitivity to endotoxin may be altered by diet, environmental and metabolic stresses. Intestinal derived endotoxin and inflammation result in suppressed appetite, activation of the immune system, and partitioning of energy and nutrients away from growth towards supporting the immune system requirements. In livestock, this leads to the suppression of growth, particularly, suppression of lean tissue accretion. In this paper, we summarize the evidence that intestinal transport of endotoxin and the subsequent inflammation leads to decrease in the production performance of agricultural animals, and we present an overview about endotoxin detoxification mechanisms in livestock.

Considering the different potential benefits of divergent fiber ingredients, the effect of 3 fiber sources on the energy and macronutrient digestibility, fermentation product formation, postprandial metabolite responses, and colon histology of overweight cats fed kibble diets was compared. Twenty-four healthy adult cats were assigned in a complete randomized block design to 2 groups of 12 animals, and 3 animals from each group were fed 1 of 4 of the following kibble diets: control (CO; 11.5% dietary fiber), beet pulp (BP; 26% dietary fiber), wheat bran (WB; 24% dietary fiber), and sugarcane fiber (SF; 28% dietary fiber). Digestibility was measured by the total collection of feces. After 16 d of diet adaptation and an overnight fasting, blood glucose, cholesterol, and triglyceride postprandial responses were evaluated for 16 h after continued exposure to food. On d 20, colon biopsies of the cats were collected under general anesthesia. Fiber addition reduced food energy and nutrient digestibility. Out of all of the fiber sources, SF had the lowest dietary fiber digestibility (P < 0.05), causing the largest reduction of dietary energy digestibility (P < 0.05). The higher fermentability of BP resulted in reduced fecal DM and pH, greater fecal production [g/(cat•d); as-is], and greater fecal concentration of acetate, propionate, and lactate (P < 0.05). For most fecal variable, WB was intermediate between BP and SF, and SF was similar to the control diet except for an increased fecal DM and a firmer feces production for the SF diet (P < 0.05). Postprandial evaluations indicated reduced glucose mean concentration and area under the glucose curve in cats fed the SF diet (P < 0.05). Colon mucosa thickness, crypt area, lamina propria area, goblet cell area, crypt mean size, and crypt in bifurcation did not vary among the diets. According to the fiber solubility and fermentation rates, fiber sources can induce different physiological responses in cats, reduce energy digestibility, and favor glucose metabolism (sugarcane fiber), or improve gut health (beet pulp).

The Cell Biology Symposium titled "Novel technologies and novel insights" was held at the Joint Annual Meeting of the American Dairy Science Association and the American Society of Animal Science in New Orleans, Louisiana, July 10-14, 2011. The purpose of the symposium was to provide the animal science community with an update on novel molecular technologies that allow new insights into genome structure and function in livestock.

Phytic acid (IP₆) and myo-inositol phosphate esters (IP_1-5), including IP₅ isomers prepared chemically and enzymatically with bacterial and fungal phytases, were examined for their effects on protein aggregation of soy protein and β-casein, interaction with Fe³⁺, and pepsin activity. The results indicated that the aggregating capabilities of IP esters (IP_1-6) on the 2 proteins decreased dramatically from IP₆ to IP₅ and became negligible with IP_1-4. Among the IP₅ isomers tested, InsP₅(1,2,3,4,5) produced by 6-phytase was slightly less powerful in aggregating protein than InsP₅(1,2,4,5,6) produced by 3-phytase (P = 0.001). For protein hydrolysis, IP esters of IP_3-4 still showed inhibition of pepsin though to a lesser extent than IP_5-6. The in vitro data with IP_1-5 generated with microbial 3- and 6-phytases indicate that for complete alleviation of pepsin inhibition, IP₆ needs to be broken down to IP_1-2. In contrast to the aggregation with protein, the reactivity of IP_1-6 toward Fe³⁺decreased proportionally from IP₆ to IP_3. Based on the radical decrease in turbidity of IP₆ -protein complex observed, as a result of IP₆ dephosphorylation to IP₅, a novel qualitative and semi-quantitative phytase plate assay was established using IP₆-protein complex incorporated into an agarose petri-dish as substrate. Phytase activity was shown as the development of clear halos on the agarose plate with time. This simple phytase plate assay method can be used at animal farms, control laboratories and even for the screening of engineered phytase variants. The current study, thus, stresses the importance of the efficient hydrolysis of IP₆ at lower pH range to alleviate the negative effect of phytic acid and its degradation products on protein and Fe³⁺ digestion.

Improved understanding of the biology of traits of livestock species necessitates the use and combination of information that is stored in a variety of different sources such as databases and literature. The ability to effectively combine information from different sources, however, depends on a high level of standardization within and between various resources, at least with respect to the used terminology. Ontologies represent a set of concepts that facilitate standardization of terminology within specific domains of interest. The biological mechanisms underlying quantitative traits of farm animal species related to reproduction and host pathogen interactions are complex and not well understood. This knowledge could be improved through the availability of domain specific ontologies that provide enhanced possibilities for data annotation, data retrieval, data integration, data exchange, data analysis, and ontology-based searches. Here we describe a framework for domain specific ontologies and the development of two first-generation ontologies: the Reproductive Trait and Phenotype Ontology (REPO) and the Host Pathogen Interactions Ontology (HPIO). In these first-generation ontologies, we focused on ‘female fertility in cattle’ and ‘interactions between pigs and Salmonella’. Through this, we contribute to the global initiative towards the development of an Animal Trait Ontology (ATO) for livestock species. To demonstrate its usefulness, we show how REPO can be used to select candidate genes for fertility. Availability: The Reproductive Trait and Phenotype Ontology (REPO) is at NCBO BioPortal: http://bioportal.bioontology.org/ontologies/1552. The Host Pathogen Interaction Ontology (HPIO) is at NCBO BioPortal: http://bioportal.bioontology.org/ontologies/1569.

Studies on the environmental consequences of stress are relevant for economic and animal welfare reasons. We recently reported that long-term heat stressors (31 ± 1ºC and 36 ± 1ºC/10 h per day) applied to broiler chickens from d 35 to 42 of life increased serum corticosterone concentrations, decreased performance parameters and the macrophage oxidative burst and produced mild, multifocal acute enteritis. Being cognizant of the relevance of acute heat stress on tropical and subtropical poultry production, we designed the current experiment to analyze, from a neuroimmune perspective, the effects of an acute heat stress (31 ± 1ºC for 10 h in the 35^th day of life) on serum corticosterone, performance parameters, intestinal histology and peritoneal macrophage activity in chickens. We demonstrated that the acute heat stress increased serum corticosterone concentrations and mortality and decreased food intake, body weight gain and feed conversion (P < 0.05). We did not find changes in the relative weights of the spleen, thymus and bursa of Fabricius (P > 0.05). Increases in the basal and the S. aureus-induced macrophage oxidative bursts and a decrease in the percentage of macrophages performing phagocytosis were also observed. Finally, mild, multifocal acute enteritis, characterized by the increased presence of lymphocytes and plasmocytes within the jejunum’s lamina propria, was also observed. We found that the stress-induced hypothalamic-pituitary-adrenal (HPA) axis activation was responsible for the negative effects observed on chicken performance and immune function as well as for the changes in the intestinal mucosa. The data presented here corroborate with that presented in other studies in the field of neuroimmunomodulation and open new avenues for the improvement of broiler chicken welfare and production performance.

Heat stress compromises efficient animal production by marginalizing nutrition, management, and genetic selection efforts to maximize performance endpoints. Modifying farm infrastructure has yielded modest success in mitigating heat stress-related losses yet poor production during the summer remains arguably the costliest issue facing livestock producers. Reduced output (i.e., milk yield, muscle growth, etc.) during heat stress was traditionally thought to result from decreased nutrient intake (i.e., a classic biological response shared by all animals during environmental-induced hyperthermia). Our recent observations have begun to challenge this belief and indicate heat-stressed animals employ novel homeorhetic strategies to direct metabolic and fuel selection priorities independently of nutrient intake or energy balance. Alterations in systemic physiology support a shift in carbohydrate metabolism, evident by increased basal and stimulated circulating insulin levels. Perhaps most intriguing given the energetic shortfall of the heat-stressed animal is the apparent lack of basal adipose tissue mobilization coupled with a reduced responsiveness to lipolytic stimuli. Thus, the heat stress response markedly alters post-absorptive carbohydrate, lipid, and protein metabolism independently of reduced feed intake through coordinated changes in fuel supply and utilization by multiple tissues. Interestingly, the systemic, cellular and molecular changes appear conserved amongst different species and physiological states. Ultimately, these changes result in the reprioritization of fuel selection during heat stress, which appears to be primarily responsible for reduced ruminant animal productivity during the warm summer months.

Data from 4 separate beef cattle feedlot experiments which were conducted at the Southeast Colorado Research Center (SECRC) in Lamar, CO in 2001, 2003, 2004, and 2007 were utilized in a retrospective longitudinal study investigating possible relationships between daily water consumption (WI), DMI, and weather parameters. The data set consisted of 8,209 records from 4 years (2001, 2003, 2004 and 2007) with pen based daily WI (L•head^-1) and DMI measurements and calculated daily steer BW from April to October in each year. Daily weather data were obtained from the weather station located at Lamar Municipal Airport located approximately 1.9 km from SECRC. Data collected consisted of: daily high, low, and mean daily temperature (°C), high, low, and mean humidity (%), high, low, and mean sea level pressure (mm), mean wind speed (km•h^-1), total precipitation (cm), and average daily wind direction (cosine of radians from due north). Univariate analysis demonstrated that the continuous variables of BW, humidity, and sea level pressure were negatively related (P < 0.0001); whereas, DMI, temperature the previous day, daily temperature, change in temperature from the previous day, average wind speed, and the temperature-humidity index (THI) were positively related (P < 0.001) to daily WI. There was a trend (P < 0.06) for the cosine of wind direction (1 = due north and -1 = due south) to be negatively related to WI. The multivariate, parsimonious model predicting average daily WI included (P < 0.05) average humidity, average humidity squared, high temperature squared, high humidity squared, low temperature, low temperature squared, low humidity, average sea level pressure, average wind speed, average daily BW, high sea level pressure, low sea level pressure, high humidity, and low humidity. The generalized R² of the parsimonious multivariate model was 0.32. These results indicate that BW and numerous weather factors are related to WI by yearling feedlot steers. Dry matter intake had minimal impact on WI for yearling feedlot steers consuming steam-flaked corn based high concentrate diets from mid-spring to early fall.

At face value there are clear and established roles for prolactin (PRL) in the regulation of mammary gland growth, lactogenesis, and galactopoiesis. However, these actions of PRL do not occur in isolation, but rather are finely attuned to, and coordinated with, many local, reproductive, and metabolic events in the female. Hence, to understand PRL action at the level of the mammary glands is to understand the systemic and local contexts in which it acts and functions. Herein we review the functions of PRL, its receptors, and the pathways leading to the phenotypes it evokes within the mammary glands, including growth and lactation, across a variety of species. At one level, the actions of PRL are mediated by several PRL receptor (PRLR) isoforms including its long form and various short PRLR variants that are generated by alternative splicing in a species- and tissue-dependent manner. In turn, these PRLR activate a variety of intracellular signaling cascades. We also focus on how PRL coordinates with other endocrine cues to impart its effects on the mammary glands, where the ovarian hormones can independently and substantially modulate PRL action. Many of these effects of PRL are also realized at the local level of the mammary glands, either through the autocrine or paracrine synthesis of a multitude of molecules and transcription factors, or through its effects on adjacent supporting tissues including the mammary vasculature. Taken together, it is clear that PRL directs a variety of mechanisms during growth and function of the mammary gland and is deserving of its classification as the ‘master hormone’.

Porcine reproductive and respiratory syndrome (PRRS) causes decreased reproductive performance in breeding animals and increased respiratory problems and morbidity in growing animals, which results in significant economic losses in the swine industry. Vaccination has generally not been effective in the prevention of PRRS, partially due to the rapid mutation rate and evolution of the virus. The objective of the current study was to discover the genetic basis of host resistance or susceptibility to the PRRS virus through a genome wide association study using data from the PRRS Host Genetics Consortium PRRS-CAP project. Three groups of ~190 commercial crossbred pigs from one breeding company were infected with PRRS virus between 18 and 28 days of age. Blood samples and body weights were collected up to 42 days post infection (dpi). Pigs were genotyped with the Illumina Porcine 60k Beadchip. Whole genome analysis focused on viremia at each day blood was collected, and weight gains from 0 to 21 dpi (WG21) or 42 dpi (WG42). Viral load (VL) was quantified as area under the curve from 0 to 21 dpi. Heritabilities for WG42 and VL were moderate at 0.30 and litter accounted for an additional 14% of phenotypic variation. Genomic regions associated with VL were found on chromosomes 4 and X, and on 1, 4, 7, and 17 for WG42. The 1 Mb region identified on chromosome 4 influenced both WG and VL, exhibited strong linkage disequilibrium, and explained 15.7% of the genetic variance for VL and 11.2% for WG42. Despite a genetic correlation of -0.46 between VL and WG42, genomic estimated breeding values (GEBV) for this region were favorably and nearly perfect correlated. The favorable allele for the most significant SNP in this region had a frequency of 0.16 and estimated allele substitution effects were significant (p < 0.01) for each group when the SNP was fitted as a fixed covariate in a model that included random polygenic effects using ASREML, with overall allele substitution estimates of -4.1 units for VL (phenotypic SD = 6.9), and 2.0 kg (phenotypic SD = 3 kg) for WG42. Candidate genes in this region on SSC4 include the interferon induced guanylate-binding protein gene family. In conclusion, host response to experimental PRRS virus challenge has a strong genetic component and a QTL on chromosome 4 explains a substantial proportion of the genetic variance in the studied population. These results could have a major impact in the swine industry by enabling marker-assisted selection to reduce the impact of PRRS but need to be validated in additional populations.

The objective of this research was to investigate the fate of free ferulic acid (FA) in sheep. Ferulic acid is normally present in plants, bound to the indigestible cell wall. If the FA present in a ruminant diet is released from the cell wall with feed pretreatment methods, FA may be released into the rumen for digestion and/or absorption into the bloodstream. Eight male Dorset x Finn lambs were randomly assigned to 1 of 4 treatment (trt) concentrations, 0 (control), 3, 6 or 9 g/d free FA as part of a replicated 4 x 4 Latin square design. Lambs were housed individually and consumed chopped alfalfa hay (Medicago sativa) (22.8% CP, 39.3% NDF, 0.73 Mcal/kg NE_g) ad libitum and 350 g corn grain (Zea mays L.) (9.1% CP, 11.2% NDF, 1.52 Mcal/kg NE_g) once daily at 0800 h. Basal levels of FA in hay, grain, blood, feces and urine were established following a 14 d adjustment to diet and housing. An oral dose of free FA was administered for 5 d via bolus after each morning feeding, after which hay, grain, blood, feces and urine were sampled. Body weights were recorded at the beginning and end of each trt, and DMI was measured daily during trt periods. In addition to trt, each lamb ingested a daily average of 3.78 g FA in its bound form via the offered hay (2.67 mg/g FA; 1.0 kg/d DMI) and corn (3.17 mg/g FA; 0.35 kg/d DMI). The FA administered had a quadratic effect on average hay DMI (1.25, 1.41, 1.41 and 1.29 kg/d for 0, 3, 6 or 9 g/d FA trt; P < 0.01; SE = 58.9 g), but lamb BW did not change as a result of FA trt (P = 0.28). The NDF level and amount of FA in refusals were not affected by trt, (P = 0.30; P = 0.82, respectively). Fecal FA did not differ among trt or when compared to basal FA (P = 0.53) while urine FA increased as FA dose increased (P < 0.01), indicating that free FA was absorbed and transferred into urine. No free FA was found in the plasma analyzed, suggesting that disappearance from the blood of absorbed free FA occurred within the 5 h that passed between bolus dosage and blood collection. An in vitro analysis was conducted to assess the degree of inhibition of microbial NDF digestion caused by FA supplementation. In vitro NDF disappearance was not inhibited as a result of FA treatment (P = 0.80). These data in combination with the results of the lamb study indicate that free FA as 0.24, 0.43 and 0.70 percent of DMI in lambs is absorbed and excreted in the urine as opposed to the feces with no apparent effects on rumen microbial NDF digestion.

Cumulus cell (CC) apoptosis is inversely correlated with embryonic development in vitro. Therefore, inhibition of CC apoptosis is important for proper embryonic development and quality. Retinoic acids (all-transRA and 9-cisRA) are the natural components of retinoids and the 9-cisRA is the physiologically active metabolite of retinoic acid in vitro. During in vitro maturation, 9-cisRA enhances oocyte competence through multiple mechanisms affecting the oocyte and the preimplantation embryo; however, the effect of 9-cisRA on CC apoptosis has yet to be elucidated. The aim of the present study was to evaluate the effect of 9-cisRA on CC apoptosis and to identify the molecular mechanism underlying that effect. Bovine slaughterhouse cumulus-oocyte-complexes (COC) were matured in vitro in the absence or presence of 5 nM 9-cisRA. Cumulus cells were collected from immature and matured COC for the detection of apoptosis and gene expression analysis. Results showed that 9-cisRA reduced the number of apoptotic CC by about 2.7-fold (P < 0.023) compared to the control. However, apoptosis is rare in CC of immature COC (0.01% ± 0.001). Transcripts involved in the caspase cascade were down-regulated upon exposure to 9-cisRA, including tumor necrosis factor alpha (TNF-α, 11.1-fold, P < 0.001), tumor necrosis factor alpha receptor 1 (TNFR1, 2.3-fold, P < 0.01), caspase 9 (CASP9, 2.0-fold, P < 0.031), caspase 8 (CASP8, 2.2-fold, P < 0.012), and caspase 3 (CASP3, 2.1-fold, P < 0.006), while anti-apoptotic B-cell lymphoma 2 (BCL2) transcript was increased (3.1-fold, P < 0.004) compared to the control. In addition, 9-cisRA inhibited mitogen activated protein kinase mRNA expression in CC, including extracellular signal-regulated kinase 1/2 (ERK1, 2.7-fold, P < 0.02; ERK2, 2.7-fold, P < 0.03), and c-Jun N-terminal kinase (JNK, 1.6-fold, P < 0.044), as well as the activator protein-1 (AP1) family members c-jun (1.6-fold, P < 0.041) and c-fos (2.0-fold, P < 0.06). The transcript abundances of TNF-α, TNFR1, CASP9, CASP8, CASP3, ERK1, ERK1, JNK, and BCL2 were increased while c-fos and c-jun mRNA expression was decreased in the matured CC. In conclusion, the present study suggests that 9-cisRA inhibits CC apoptosis during in vitro maturation of bovine COC.

Three experiments were designed to evaluate methods to optimize the use of sex-sorted sperm in timed AI (TAI) programs for suckled beef cows. In all 3 experiments, suckled Bos indicus cows were synchronized using an intravaginal progesterone (P4) device during 8 d and a 2.0-mg injection of i.m. estradiol benzoate (EB) at device insertion. The females received PG and equine chorionic gonadotropin (300 IU) at P4 device removal and 1.0 mg of EB 24 h later. The cows were timed inseminated 60 to 64 h after P4 device withdrawal. All cows had their ovaries scanned by transrectal ultrasound at TAI to indentify and to measure the largest follicle (LF) present. In Experiment 1, a total of 853 cows had their LF classified as < 9 mm or ≥ 9 mm at the time of TAI; these cows were then randomly assigned to 4 groups according to their LF diameter (< 9 mm or ≥ 9 mm) and the type of sperm used (sex-sorted or non-sex-sorted). There was an interaction (P = 0.02) between the type of sperm and LF diameter beginning at TAI (non-sex-sorted ≥ 9 mm = 58.9%^a [126/214]; non-sex-sorted < 9 mm = 49.5%^b [106/214]; sex-sorted ≥ 9 mm = 56.8%^ab [134/236]; and sex-sorted < 9 mm = 31.2%^c [59/189]). In Experiment 2, suckled cows (n = 491) were classified immediately before TAI as having displayed estrus or not (estrus or no estrus),, between P4 device removal and TAI. These cows were randomly assigned to 4 groups according to the occurrence of estrus and the type of sperm (sex-sorted or non-sex-sorted). There were effects of the occurrence of estrus (P = 0.0003) and the type of sperm (P = 0.05) on pregnancy per AI (P/AI; no estrus, non-sex-sorted = 43.6% [27/62]; estrus, non-sex-sorted = 58.5%; [107/183]; no estrus, sex-sorted = 33.9% [21/62], and estrus, sex-sorted = 50.0% [92/184]); however, no interaction between the occurrence of estrus and type of sperm was observed (P = 0.87). In Experiment 3, a total of 200 suckled cows presenting LF ≥ 9 mm at TAI were randomly assigned to receive sex-sorted sperm deposited into the uterine body (n = 100) or into the uterine horn ipsilateral to the recorded LF (n = 100). No effect of deeper artificial insemination on P/AI was found (P = 0.57). Therefore, the LF diameter at TAI and the occurrence of estrus can be used as selection criteria to identify cows with higher odds of pregnancy to receive sex-sorted sperm in TAI programs. In addition, performing TAI with sex-sorted sperm deeper into the uterus did not alter the pregnancy results.

Lysozyme is one of the best characterized antimicrobial proteins in egg white. Three phenotypes of egg white lysozyme in Japanese quail, Coturnix japonica, (namely F, FS, and S) were observed by acid polyacrylamide gel electrophoresis. The fast (F) phenotype showed faster mobility on Acid-PAGE than the slow (S) phenotype. Comparison of the coding sequences for lysozyme derived from the S and F phenotypes revealed a nonsynonymous single nucleotide polymorphism (SNP) at nucleotide position 115 from the translation initiation site, which alters amino acid sequence of lysozyme. This nonsynonymous SNP converted glutamine (Q) in the S phenotype to lysine (K) in the F phenotype at amino acid residue 21 of mature lysozyme (Q21K). Here, we investigated the effect of these phenotypes on muramidase activity, antibacterial activity and hatchability. Muramidase activity towards isolated cell walls of Micrococcus lysodeikticus was in the order; F allozyme > S allozyme > chicken, but no significant difference was found among the three (P > 0.05). Antibacterial activity against live Staphylococcus aureus cells was significantly higher for the F allozyme than the S allozyme from 20 h after incubation (P < 0.05). For the antibacterial effects against live Escherichia coli cells, the activity of F was significantly higher than that of S at 16 h after incubation (P < 0.05). Hatchability was estimated for reciprocal crosses of Japanese quail with the FF and SS genotypes. Hatchability was 92.5% in FF male x SS female crosses and 87.2% in SS male x FF female crosses. A Cochran-Mantel-Haenszel test revealed a significant difference between the crosses (P < 0.05), which suggested that the female-derived S phenotype led to improved rates of hatching. Our results suggest that the nonsynonymous SNP in Japanese quail lysozyme influences the electrophoretic migration, muramidase activity, and antibacterial activity of the protein, in addition to the hatchability of the eggs. These results demonstrate, for the first time, a significant difference in antibacterial activity and hatchability between two lysozyme phenotypes in Japanese quail.

Experiments were conducted in sheep to determine excretory characteristics of sodium chlorate after a single oral dose. In Exp. 1 lambs (n = 16; age = 8.1 ± 1.7 d; BW = 8.2 ± 1.1 kg; mean ± SD) were dosed orally with 0, 30, 60, or 90 mg/kg BW of sodium chlorate. Twenty-four h after exposure chlorate residues were dose dependent (P < 0.05) in small intestinal contents, serum, and urine, but chlorate residues were not consistently detected in cecal or colonic contents. In Exp. 2, non-pregnant yearling ewes (BW = 74.8 ± 5.6 kg; mean ± SD) were orally dosed with 0, 150, 300, or 450 mg/kg BW of sodium chlorate. Across dose, chlorate residues averaged from 47 to 114, 0.6 to 4.5, and not detectable to 0.2 ppm at 24, 48, and 72 h, respectively, in serum of treated animals; in feces, residues averaged 29 to 82, 0.8 to 14, and not detectable to 1.2 ppm at the same respective time periods. In Exp. 3 six lactating ewes (BW = 76.3 ± 8.0 kg) were dosed orally with 450 mg/kg BW of sodium chlorate; residues were measured in serum, milk, urine, and feces in periods encompassing 0 to 8, 8 to 16, 16 to 24, 24to 32, 32 to 40, and 40 to 48 h. Chlorate residues in milk were detectable at all time periods with concentrations averaging from 287 ± 67 to 26 ± 13 ppm during the first and last collection periods, respectively. Urine contained the greatest concentration of chlorate at each time point and averaged 480 ± 268 ppm at 40 to 48 h. Depletion half-lives in serum, milk, urine, and feces were estimated to be 6.2, 27, 19, and 10 h, respectively; milk, urinary, and fecal half-lives are likely overestimated due to the fact that 8-h sample pools were used in half-life estimations. In Exp. 4, three wethers (BW = 87.1 ± 5.3 kg) each were orally dosed with 14 or 42 mg/kg BW of sodium chlorate; blood samples were serially drawn for 48 h and urine samples were collected in 0 to 8, 8 to 16, 16 to 24, 24 to 36, and 36 to 48 h. Estimates of absorption and elimination half-lives based on serum chlorate concentrations were about 0.4 and 2.5 h, respectively. Urine collected during the 6 h immediately following dosing contained the greatest concentrations of chlorate residues relative to subsequent collection periods. Rapid removal of chlorate from the gastrointestinal lumen suggests that effects of chlorate on colonic and fecal gastrointestinal bacteria may occur through mechanisms other than direct luminal contact between microbe and chlorate salts.

Because of the increasing demand for raw cuts and processed products, there is a trend to producing very heavy broilers. Breeds that are used for such kinds of production have been intensively selected for growth rate and breast meat yield, and birds are reared for a longer period than standard broilers. This study was to evaluate the effects of increasing slaughter age on technical and economic factors, including production efficiency and environmental costs, bird welfare and breast meat quality in a modern heavy broiler line. Five groups of 300 male Ross 708 chickens were reared until slaughter ages of 35, 42, 49, 56 or 63 d. Increasing age at slaughter from 35 to 63 d resulted in a 7.4-fold increase (P < 0.01) in mortality rate (5.21% vs. 0.70%). It also increased (P < 0.001) the slaughter weight and ADFI of birds 2.5 and 1.4-fold, respectively, without affecting their G:F. Under our experimental conditions, economic profit evaluated through the net gain reached a maximum at 42 d. The moisture and ammonium content of litter increased (P < 0.05 and P < 0.01, respectively) rapidly during rearing concomitantly with increased (P < 0.05) occurrence and severity of contact dermatitis and decreased (P < 0.05) walking ability and activity of birds. Thermal comfort also decreased (P < 0.05) greatly as early as 42 d of age. Changes in carcass quality occurred mainly between 35 and 56 d of age, with a progressive increase (P < 0.001) in breast and leg yield whereas body fatness was barely affected by age. Major changes in breast meat traits were observed between 35 and 49 d of age, with an increase in muscle pH measured at 15 min (P < 0.01) and 24 h (P < 0.001) post mortem, reduced (P < 0.001) lightness and drip loss. The protein and lipid content of raw breast meat also increased (P < 0.05 and P < 0.01, respectively) with age. Taking into account the main aspects of sustainability, we could recommend slaughtering chickens of heavy line at 42 d of age.

Regular removal of milk from the mammary gland is critical to maintaining milk secretion. Early studies in rodents demonstrated that changes in milking frequency influenced mammary blood flow, as well as mammary cell number and activity. Later studies in ruminants confirmed those observations and that the response was regulated locally within the mammary gland. In addition, it was discovered that increased milking frequency (IMF) during early lactation stimulated an increase in milk production that partially persisted through late lactation, indicating long-term effects on mammary function. The local mechanisms regulating the mammary response to IMF are poorly understood, although several have been proposed. To gain insight into the mechanisms underlying the mammary response to IMF, and to identify genes associated with the response, we used a functional genomics approach and conducted experiments on dairy cows exposed to unilateral frequent milking [UFM; twice daily milking (2X) of the left udder half, four-times daily milking (4X) of the right udder half]. Across multiple experiments, we were unable to detect an effect of UFM on mammary cell proliferation or apoptosis. We have, however, identified distinct transcriptional signatures associated with the mammary response to milk removal and to UFM during early lactation. Sequential sampling of mammary tissue revealed that when UFM was imposed during early lactation, at least two sets of genes were coordinately regulated with changes in differential milk production of 4X vs. 2X udder halves. Moreover, some genes were persistently differentially expressed in 4X vs. 2X udder halves after UFM and were associated with the persistent increase in milk yield. We conclude that a coordinated transcriptional response is associated with the increase in milk yield elicited by IMF during early lactation, and that the two sets of differentially expressed genes may be a marker for the autocrine up-regulation of milk production. Moreover, we propose that we have identified a novel form of imprinting associated with persistent alteration of mammary function, which we term 'lactational imprinting."

Lambing interval is a relevant reproductive indicator for sheep populations under continuous mating systems, although there is a shortage of selection programs accounting for this trait in the sheep industry. Both the historical assumption of small genetic background and its unorthodox distribution pattern have limited its implementation as breeding objective. In this manuscript, statistical performances of three alternative parametrizations (i.e., symmetric Gaussian mixed linear (GML) model, skew-Gaussian mixed linear (SGML) model, and piecewise Weibull proportional hazard (PWPH) model) have been compared in order to elucidate the preferred methodology to handle lambing interval data. More specifically, flock-by-flock analyses were performed on 31,986 lambing interval records (257.3 ± 0.2 d) from six purebred Ripollesa flocks. Model performances were compared in terms of deviance information criterion (DIC) and Bayes factor (BF). For all flocks, PWPH models were clearly preferred, they generating a reduction of 1,900 or more DIC units and providing BF estimates larger than 100 (i.e., PWPH models against linear models). These differences reduced when comparing PWPH models with different number of change points for the baseline hazard function. In four flocks, only two change points were required to minimized the DIC, whereas four and six change points were needed for the two remaining flocks. These differences evidenced a remarkable degree of heterogeneity across sheep flocks that must be properly accounted for in genetic evaluation models in order to avoid statistical biases and suboptimal genetic trends. Within this context, all six Ripollesa flocks revealed substantial genetic background for lambing interval, heritabilities ranging between 0.13 and 0.19. This study provides the first evidences about the suitability of PWPH models for lambing interval analysis, clearly discarding previous parametrizations focused on mixed linear models.

The Physiology and Endocrinology Symposium on "Factors controlling puberty in beef heifers" was held at the Joint Annual Meeting of the American Dairy Science Association and the American Society of Animal Science in New Orleans, LA, July 10 to 14, 2011. The objective of the symposium was to provide attendees with new insights and perspectives from recent research findings on puberty in beef heifers. To that end, the 2011 physiology and endocrinology symposium program was organized to review recent research findings in beef cattle puberty with a broad overview of areas affecting puberty including management, genetics, nutrition, and hormonal manipulation of the estrous cycle.

The objectives of this study were to determine nitrogen loss at different stages of growth and during the entire growing period, and to investigate the associations between nitrogen excretion and production traits in growing pigs. Data from 315 pigs of an F₂ population which originated from crossing Pietrain sires with a commercial dam line were used. Nitrogen retention was derived from protein retention as measured using the deuterium dilution technique during different stages of growth (60 to 90 kg, 90 to 120 kg and 120 to 140 kg). Pigs were fed ad libitum with two pelleted diets containing 17% (60 to 90 kg) and 16.5% (90 to 120 and 120 to 140 kg) CP. Average daily nitrogen excretion (ADNE) within each stage of growth was calculated based on the accumulated difference between average daily nitrogen intake (ADNI) and average daily nitrogen retention (ADNR). Lowest ADNE, nitrogen excretion per weight gain (NEWG) and total nitrogen excretion (TNE) were observed during growth from 60 to 90 kg. In contrast, the greatest ADNE, NEWG and TNE were found during growth from 120 to 140 kg. Statistical analyses indicated that gender, housing type, the ryanodine receptor 1 (RYR1) gene and batch influenced nitrogen excretion (P < 0.05), but the degree and direction of influences differed between growth stages. Gender differences showed that gilts excreted less nitrogen than barrows (P < 0.05), which was associated with lower feed conversion ratio (FCR; Feed:gain) and lipid:protein gain ratio. Single-housed pigs showed lower nitrogen excretion compared to group-housed pigs (P < 0.05). In comparison to other genotypes, pigs carrying genotype NN (homozygous normal) at the RYR1 locus had the lowest nitrogen excretion (P < 0.05) at all stages of growth except from 60 to 90 kg. The residual correlations indicated that NEWG and TNE have large positive correlations with FCR (r = 0.99 and 0.91, respectively) and moderate negative correlations with ADG (r = -0.53 and -0.48, respectively), for the entire growing period. Improvement in FCR, increase in ADG and reduction in lipid:protein gain ratio by one phenotypic standard deviation reduced TNE per pig by 709 g, 307 g and 211 g, respectively, over the entire growing period. The results indicate that nitrogen excretion changes substantially during growth and it can be reduced most effectively by improvement of feed efficiency and to a lesser extent through the improvement of weight gain and/or body composition.

The objective of this experiment was to investigate the effects of injectable trace minerals on humoral responses of calves receiving a viral vaccination. Beef steer calves (n = 99; average BW = 316 ± 4.2 kg), seronegative for bovine herpesvirus-1 (BHV-1) and bovine viral diarrhea virus, genotypes 1 and 2 (BVDV-1 and BVDV-2) were sourced from 2 locations. All calves, except 15 non-vaccinated (sentinel) calves, received a single dose of a multivalent modified live vaccine (Titanium 5; AgriLabs, St. Joseph, MO) containing BHV-1, BVDV-1, BVDV-2, bovine parainfluenza virus type 3, and bovine respiratory syncytial virus. Among the vaccinated calves, 2 treatments were concurrently and randomly applied based on initial serum Se status and BW; including, (1) injectable trace mineral supplement (ITM; n = 42; 7 mL subcutaneous.; MultiMin, Fort Collins, CO) containing 15, 40, 10 and 5 mg/mL of Cu, Zn, Mn (all as disodium EDTA salts) and Se (as Na selenite), or (2) Saline-injected control (Control; n = 42). As a measure of humoral immunity, neutralizing antibody titers were measured on d 0, 14, 30, 60 and 90, relative to vaccine administration. All calves were seronegative for each of the 3 viruses on d 0 and sentinel calves remained seronegative throughout the study. Serum mineral concentrations were evaluated on d 0 and 14. No differences (P ≥ 0.30) in serum Cu, Zn, Mn, or Se were observed between treatments on d 0. Control steers experienced a decrease (P < 0.001) in serum Zn and Se and ITM steers had an increase (P = 0.007) in serum Cu on d 14 relative to initial d 0 values. On d 14, serum Zn and Se concentrations were greater (P < 0.01) in ITM compared with Control steers. Vaccinated calves experienced marked increases in neutralizing antibody titers by d 30 following vaccine administration. Calves receiving ITM at the time of vaccination experienced greater (P ≤ 0.003) neutralizing antibody titers to BHV-1 on d 14, 30, and 60 compared to Control. These results demonstrate that the injectable trace mineral formulation evaluated in this study, administered concurrently to viral vaccination, does not impair humoral immune responses in beef calves. Further, concurrent administration of ITM and BHV-1 vaccine may enhance the production of neutralizing antibodies to BHV-1 in previously naïve beef calves.

The functioning of the gastrointestinal tract is under the control of the most extensive system of peripheral neurons in the body, the enteric nervous system, and the body’s largest endocrine system, the gastroenteropancreatic (GEP) endocrine system. The enteric nervous system contains 500 million neurons in large mammals, and the GEP endocrine system produces more than 30 hormones. Numerous enteric neuropathies affecting both humans and animals have been described and digestive disorders affect commercially important species such as horses and cattle. The most severe enteric neuropathies, for example, lethal white syndrome in horses or Hirschsprung’s disease in human, can be fatal. Also, horses with ileus or other digestive disorders are commonly euthanized. In this review we discuss examples of enteric neuropathies that affect agricultural animals and humans: prion disease, post-operative ileus, distal enteric aganglionosis, and infective diarrhea. Enteric neurons and glia are a location of prion proteins and are involved in transmission of the infection from gut to brain and brain to gut. Post-operative ileus is a complex disorder involving the local inhibitory effects of sympathetic nervous system activation and the release of opioids, presumably from enteric neurons. Intestinal inflammation, especially of the external muscle that includes enteric ganglia, also occurs in ileus. Congenital distal bowel aganglionosis, responsible for lethal white syndrome of horses, Hirschsprung’s disease in human, and similar conditions in mice and rats, is a fatal condition if untreated. Mutations of the same genes can cause the condition in each of these species. The only effective current treatment is surgical removal of the aganglionic bowel. Infectious diarrheas involve activation of enteric secretomotor neurons by pathogens and the toxins they produce, which causes substantial fluid loss. Strategies to target enteric neurons in the treatment of secretory diarrheas have not been developed. Disorders of enteroendocrine cells, other than gastroenteropancreatic endocrine tumors, are less well documented. However, evidence for the involvement of gut endocrine cells in a subset of patients with irritable bowel syndrome, and in the symptomology of celiac disease has been demonstrated. Further investigation of the involvement of enteric neural and endocrine signaling systems in digestive disorders, especially in agricultural and companion animals, may lead to diagnostic and therapeutic advances.

The objectives of this analysis were to estimated historic (pre-European settlement) enteric methane (CH₄) emissions from wild ruminants in the contiguous United States and compare these to present-day CH₄ emissions from farmed ruminants. The analysis included bison, elk (wapiti), and deer (white-tailed and mule). Wild ruminants such as moose, antelope (pronghorn), caribou, and mountain sheep and goat were not included in the analysis due to their natural range being mostly outside of the contiguous United States, or relatively small population sizes. Data for pre-settlement and present-day population sizes, animal body weight, feed intake, and CH₄ emission factors were adopted from various sources. Present-day CH₄ emissions from livestock were from recent United States Environmental Protection Agency estimates. The most important factor determining CH₄ emissions from wild ruminants in the pre-settlement period was the size of the bison population. Overall, enteric CH₄ emissions from bison, elk, and deer in the pre-settlement period were about 86% (assuming bison population size of 50 million) of the current CH₄ emissions from farmed ruminants in the United States. Present-day CH₄ emissions from wild ruminants (bison, elk, and deer) were estimated at 0.28 Tg/yr, or 4.3% of the emissions from domestic ruminants. Due to its population size (estimated at 25 million) the white-tailed deer is the most significant present-day wild ruminant contributor to enteric CH₄ emissions in the contiguous United States.

Distributing animals from a single breeding program to a global market may not satisfy all producers, as they may differ in market objectives and farming environments. Analytic hierarchy process (AHP) is used to estimate preferences, which can be aggregated to consensus preference values using weighted goal programming (WGP). The aim of this study was to use an AHP-WGP based approach to derive desired genetic gains for rainbow trout breeding, and to study whether breeding trait preferences vary depending on commercial products and farming environments. Two questionnaires were sent out, Q-A and Q-B. Q-A was distributed to 178 farmers from 5 continents and used to collect information on commercial products and farming environments. In this questionnaire, farmers were asked to rank the 6 most important traits for genetic improvement from a list of 13 traits. Questionnaire B (Q-B) was sent to all farmers who responded to Q-A (53 in total). For Q-B, preferences of the 6 traits were obtained using pairwise comparison. Preference intensity was given in order to quantify (in % of a trait mean; G%) the degree to which one trait is preferred over the other. Individual preferences (Ind-P), social preferences (Soc-P), and consensus preferences (Con-P) were estimated using AHP and WGP. Desired gains were constructed by multiplying Con-P with G%. The analysis revealed that the 6 most important traits were thermal growth coefficient (TGC), survival (Surv), feed conversion ratio (FCR), condition factor (CF), fillet percentage (F%), and late maturation (LMat). Ranking of traits based on average Con-P values were Surv (0.271), FCR (0.246), TGC (0.246), LMat (0.090), F% (0.081), and CF (0.067). Corresponding desired genetic gains (in % of trait mean) were 1.63%, 1.87%, 1.67%, 1.29%, 0.06%, and 0.33%, respectively. The results from Con-P values show that trait preferences may vary for different types of commercial production or farming environments. This study demonstrated that combination of AHP and WGP can be used to derive desired gains for a breeding program, and to quantify differences due to variations market demand or production environment.

The aim of this study was to find potential biomarkers for meat tenderness in bovine longissimus thoracis muscle, and to compare results from isobaric Tag for Relative and Absolute Quantitation (iTRAQ) and two-dimensional gel electrophoresis (2-DE) analysis. The experiment included 4 tender and 4 tough samples, based on shear force measurements at 7 d post mortem, from Norwegian red (NRF) young bulls, taken at 1 h post mortem. A number of the proteins which have previously been related to tenderness were found to change in abundance between tender and tough samples, both in iTRAQ (P < 0.1) and 2-DE analysis (P < 0.05). Furthermore, 3 proteins that have not previously been related to tenderness were found to significantly change in abundance between tender and tough meat samples in the present study. These include proteins related to control of flux through the tricarboxylate cycle (2-oxoglutarate dehydrogenase complex component E2 (OGDC-E2)), apoptosis (galectin-1) and regulatory role in the release of Ca²⁺ from intracellular stores (annexin A6). Even though the overlap in significantly changing proteins was relatively low between iTRAQ and 2-DE analysis, certain proteins predicted to have the same function were found in both analyses and showed similar changes between the groups, like structural proteins and proteins related to apoptosis and energy metabolism.

The present study investigated the effects of source and level of dietary fiber (DF) and feeding frequency (once vs. twice daily) on feeding motivation and plasma metabolites at four different time points post feeding. Sixty pregnant sows (4 blocks of 15 sows) were allocated to 1 of 5 diets within blocks. Four diets were restricted (approx. 35 MJ ME/d): a barley/wheat control diet (171 g DF/kg DM; 12 g DF/MJ ME), and 3 fiber diets formulated to contain 35% DF by including pectin residue (323 g DF/kg DM; 25 g DF/MJ ME), potato pulp (404 g DF/kg DM; 29 g DF/MJ ME), or sugar beet pulp (367 g DF/kg DM; 25 g DF/MJ ME). The fifth diet was a mixture including an equal amount of the 3 fiber diets offered semi ad libitum (354 g DF/kg DM; 25 g DF/MJ ME). The experimental period included 2 periods of 4 wk each. Restricted fed sows were fed once daily (0800 h) during the first period and twice daily (0800 and 1500 h) during the second period, or vice versa. Semi ad libitum fed sows had access to feed 6 times a day in both periods. In each period, the feeding motivation was assessed in an operant conditioning test, and samples of peripheral blood were taken in a balanced design, at 0900, 1200, 1900 and 0700 h, corresponding to 1, 4, 11 and 23 h after feeding for restricted sows fed once daily. No differences in the feeding motivation were found between the 4 restricted diets at any of the time points post feeding, but semi ad libitum fed sows had a lower feeding motivation (P < 0.001). Among the restricted fed sows, feeding twice daily resulted in lower feeding motivation at 1900 h (P < 0.001) and at 0700h (P < 0.05) compared to feeding once daily, but not at 0900 and 1200 h, indicating that feeding twice daily reduced feeding motivation during the night compared to feeding once daily. Among restricted fed sows, plasma levels of short-chain fatty acids (SCFA) were higher in sows fed high fiber diets compared to the control (P = 0.02). Nonesterified fatty acid (NEFA) was lowest in sows on the control diet and highest in sows on the potato diet, whereas sows on the pectin and sugar beet diets were intermediate (P < 0.001). Less diurnal variation in glucose (P < 0.001) was seen in sows on high fiber diets. In spite of the found effects on plasma metabolites, the applied level of fiber in the diet of restrictedly fed sows did not reduce their feeding motivation irrespective of fiber source.

Feedlot producers often exceed NRC recommendations for vitamin A and D supplementation, however increased concentrations of these vitamins have been shown to limit adipocyte differentiation in vitro. A feedlot trial was conducted using 168 Angus crossbred steers (BW = 284 ± 0.4 kg) allotted to 24 pens. The experiment had a 2 x 2 factorial arrangement of treatments: no supplemental vitamin A or D (NAND), 3,750 IU vitamin A/kg dietary DM with no supplemental vitamin D (SAND), no supplemental vitamin A and 1,860 IU vitamin D/kg dietary DM (NASD), and 3,750 IU and 1,860 IU vitamin A and D/ kg dietary DM (SASD), respectively. Serum, liver, and intramuscular and subcutaneous adipose tissue retinol concentrations were decreased in (P < 0.001) in cattle fed the no supplemental vitamin A diets (NAND and NASD combined) compared with those consuming supplemental vitamin A (SAND and SASD combined) diets. In addition, intramuscular retinol concentration was 38% less than in the subcutaneous depot. Serum 25(OH)D₃ concentrations were reduced (P < 0.001) during the first 70 d when cattle were fed no supplemental vitamin D diets (NAND and SAND combined); however, liver 25(OH)D₃ concentrations remained unchanged (P > 0.10) through d 184. Serum and liver 25(OH)D₃ concentrations increased (P < 0.001) with vitamin D supplementation (NASD and SASD combined). The DMI, ADG, G:F, and morbidity were not affected (P > 0.10) by dietary concentration of vitamin A or D. There were vitamin A and D interactions (P < 0.03) for backfat thickness and USDA Yield grade. Cattle fed the NAND diet had greater (P < 0.03) Yield grades than other treatments due to greater (P < 0.005) 12^th rib backfat thickness in NAND steers than the NASD and SAND steers. Vitamin D concentrations were attenuated and minimal carcass adiposity responses to vitamin D supplementation were observed. Feeding a diet without supplemental vitamin A increased (P < 0.05) Quality grades and marbling scores, and tended (P = 0.06) to increase ether extractable lipid of the LM. As retinol and 25(OH)D₃ concentrations in feedlot cattle declined as a result of a lack of dietary supplementation, adipose accretion increased resulting in elevated Quality and Yield grades. Withdrawal of supplemental vitamin A and/or D from the finishing diet of feedlot beef cattle had minimal impact carcass composition.

Two experiments were conducted to determine the effects of wet distillers grains plus solubles (WDG; < 15% sorghum grain) concentration in steam-flaked corn (SFC) diets on feedlot performance, carcass characteristics, ruminal fermentation, and diet digestibility. In Exp. 1, 600 crossbred steers (364 ± 35 kg BW) were used in a randomized complete block design with 8 replications/treatment. Dietary treatments consisted of a dry-rolled corn (DRC) control diet without WDG, a SFC control without WDG, and SFC with 4 WDG concentrations (15, 30, 45, 60% DM basis) replacing SFC, cottonseed meal, urea, and yellow grease. Final BW, ADG, G:F, HCW, and 12^th rib fat depth were greater (P ≤ 0.05) for SFC compared with DRC. Dry matter intake tended (P = 0.06) to be greater for DRC compared with SFC. Final BW, ADG, G:F, HCW, 12^th rib fat depth, and marbling score decreased linearly (P < 0.01) with increasing WDG concentration. In Exp. 2, six ruminally and duodenally cannulated crossbred steers (481 ± 18 kg BW) were used in a 6 x 6 Latin square design using the same diets as Exp. 1. Ruminal, postruminal, and total tract OM and NDF digestibility were not different (P > 0.14) for DRC compared with SFC. Ruminal and total tract starch digestibility were greater (P < 0.01) for SFC compared with DRC. Dry matter and OM intake were not different (P ≥ 0.43) among WDG treatments. Ruminal and total tract OM digestibility decreased linearly (P < 0.01) with increasing WDG concentration. Intake, ruminal digestibility, and total tract digestibility of NDF increased linearly (P < 0.01) with increasing WDG concentration. Starch intake decreased linearly (P < 0.01) with increasing WDG concentration. Ruminal starch digestibility increased (P = 0.01) with increasing concentration of WDG. Total tract starch digestibility decreased quadratically (P < 0.01) with increasing concentration of WDG. Feeding SFC improved steer performance compared with DRC. The concentration of wet distillers grains with solubles and corn processing method influences nutrient digestibility and ruminal fermentation. The addition of WDG in SFC-based diets appears to negatively impact animal performance by diluting the energy density of the diet.

The objective of this study was to investigate the response of sarcoplasmic proteins in bovine longissimus muscle to low-voltage electrical stimulation (ES, 80 V, 35 s) after dressing and its contribution to meat tenderization at early postmortem time. Proteome analysis showed that ES resulted in lower (P < 0.05) phosphorylation levels of creatine kinase M chain, fructose bisphosphate aldolase C-A, β-enolase and pyruvate kinase at 3 h postmortem. Zymography indicated an earlier (P < 0.05) activation of µ-calpain in ES muscles. Free lysosomal cathepsin B&L activity increased faster (P < 0.05) in ES muscles up to 24 h. Immunohistochemistry and transmission electron microscopy further indicated that lysosomal enzymes were released at early postmortem time. ES also induced ultrastructural disruption of sarcomeres. In addition, ES accelerated (P < 0.05) depletion of ATP, phosphate creatine and glycogen, as well as pH decline and more preferred pH/temperature decline mode. Finally, ES accelerated meat tenderization with lower (P < 0.05) shear force values than control over testing time. A possible relationship was suggested between change in phosphorylation level of energy metabolic enzymes and postmortem tenderization of beef. Our results suggested the possible importance of activation of µ-calpain, phosphorylation of sarcoplasmic proteins and release of lysosomal enzymes for ES-induced tenderization of beef muscle.

A total of 42 F₁ Red Angus progeny from sires divergent in maintenance energy (ME_M) EPD were analyzed to determine whether selecting for sire ME_M alters end-product meat quality. Data from animals were grouped based on the divergence of their sire’s ME_M EPD from the Red Angus Association reported breed average and defined as either high or low. The assumption being that high ME_M cattle are less efficient as their maintenance requirements represent a larger proportion of their dietary intake. Steer progeny (n=7) from the high group produced bottom round steaks with a greater a* color value (p = 0.02) after 5 d in a simulated retail display when compared to the bottom round steaks from the low group (n=18). The bottom round steaks from the high group had a greater b* color value at d 1 (p = 0.03) and d 5 (p = 0.01) of retail display. Samples from the biceps femoris were taken at 12 (from both steers and heifers) and 15 mo (from steers only) of age for fiber type proportion analysis. At 12 mo age steers from the low group had more type I fibers (p = 0.02), whereas steers from the high group had more type IIb fibers (p = 0.01). Furthermore, samples from the steers of the low group at 15 mo had more type I fibers (p = 0.02) and steers from the high group maintained more type IIb fibers (p = 0.02). No changes in fiber type proportions were observed between the high and low ME_M EPD heifers (n=17). Relative mRNA abundance of genes involved in the synthesis, storage and breakdown of glycogen were analyzed as a parameter important for meat quality, but no statistical differences were observed. At 12 mo age, glycogenin (glyc) was negatively correlated with the proportion of type IIa fibers (r = -0.32 and p = 0.12) as well as with the proportion of type IIb fibers (r = -0.42 and p = 0.03) in the biceps femoris of the steers. In samples taken from the biceps femoris at 15 mo age glyc was negatively correlated with the proportion of type IIa fibers (r = -0.42 and p = 0.03) in the steers. This indicates that relative mRNA expression of glyc may serve as a marker of muscle glycogen storage capacity in steers. Thus selection for efficient Red Angus beef cattle based on sire ME_M EPD does not adversely affect meat quality in F₁ progeny, based on the parameters assessed in this study. Furthermore, selection for progeny from low ME_M EPD sires may improve fresh meat quality within Red Angus beef cattle.

This study was conducted to investigate relationships between mitochondrial respiratory chain complex activities, feed efficiency, and carcass traits in sheep. A group of Ghezel male lambs sired by a single ram were randomly allotted to individual pens. The lambs were fed ad libitum with a fattening diet containing 30% roughage (corn silage and alfalfa hay) and 70% concentrate for 70 d to individually phenotype each lamb for FCR, adjusted FCR (aFCR), and residual feed intake (RFI). The lambs were then humanely killed and liver, abdominal fat, pelvic fat, cardiac fat, warm and cold carcass weights, as well as the cross sectional area of the LM and the fat depth over the 12^th rib were determined. A portion of LM was obtained to determine mitochondrial protein and respiratory chain complex activities (Complex I to V). Statistical analysis was carried out based on lambs exhibiting high and low RFI (n = 8), FCR (n = 8), or aFCR (n = 8) phenotypes. The high RFI lambs consumed 110 g more feed daily (P < 0.05) than did the low RFI phenotype with no difference in ADG. Conversely, there was no difference in feed intake between low or high FCR groups but the low FCR phenotype gained 70 g more (P < 0.05) per day compared to the high FCR phenotype. It was determined that all 5 respiratory chain complex activities were greater (P < 0.05) in the low RFI compared to the high RFI phenotype with significant (P < 0.001) negative correlation coefficients between RFI and respiratory chain complex activity. When efficiency was assessed using FCR, only activities of respiratory chain complexes III, IV, and V were less (P < 0.05) in the low-FCR compared to the high-FCR phenotype and there were no differences (P > 0.1) in respiratory chain complex activities between groups when FCR was adjusted for metabolic BW (aFCR). There were no differences (P > 0.1) in carcass traits among any of the feed efficiency phenotypes. The results suggest that the inclusion of respiratory chain complex activities in breeding programs may be helpful in selecting for low-RFI phenotype sheep.

Three experiments were conducted to evaluate methods of immunization against GnRH on antibody titer, luteal activity, and pregnancy in beef heifers. Experiment 1 evaluated the efficacy of adjuvants with 30 heifers. Control heifers were immunized against human serum albumin (HSA) emulsified in Freund's complete adjuvant (FCA). The other 4 treatments contained GnRH conjugated to HSA (HSA-GnRH) emulsified in either FCA, Freund's incomplete adjuvant (FIA), DEAE dextran (DD)+mineral oil (MO), or DD+FIA. Treatment was in the mammary gland for all experiments. Titers against GnRH for heifers immunized against HSA-GnRH with FCA, DD+MO, or DD+FIA were greater than titers for HSA-GnRH with FIA or control heifers (P < 0.01). Body weight was reduced (P < 0.05) in control and FCA heifers compared with FIA, DD+MO, and DD+FIA. Heifers immunized with DD+MO and DD+FIA had fewer granulomas in mammary glands than heifers treated with FCA (P < 0.01). In Experiment 2, 36 heifers were used to determine the effect of the protein conjugated to GnRH on titers against GnRH. Heifers (6 per treatment) received a primary immunization against GnRH conjugated to HSA (HSA-GnRH), ovalbumin (OA-GnRH), or keyhole limpet hemocyanin (KL-GnRH), or heifers were immunized against each carrier protein. Antigens were emulsified in DD+FIA. Immunization of heifers against OA-GnRH, KL-GnRH, or HSA-GnRH suppressed luteal activity (P < 0.01) for 23, 16, and 12 wk, respectively, and antibody titers against GnRH were greater (P < 0.01) for 19, 5, and 7 wk, respectively, compared with heifers immunized against the carrier proteins. In Experiment 3, 90 heifers were used to determine the effect of immunization against GnRH on ovarian activity and pregnancy rate. Heifers (30 per treatment) received a primary and 2 or 3 booster immunizations against GnRH conjugated to OA and controls received a primary and 2 booster immunizations against OA. All antigens were emulsified in DD+FIA. At 8 wk after primary immunization, heifers were exposed to fertile bulls for 24 wk. Pregnancy rate was less (P < 0.01) for 3-booster (13%) compared with control (83%) and 2-booster (62%) heifers. We conclude that immunization against GnRH, conjugated to OA and emulsified in DD+FIA, does not influence ADG and produces sufficient titers against GnRH to prevent estrous cycles with few mammary granulomas. Immunization against GnRH with 3 booster immunizations prevented luteal activity and pregnancy in most beef heifers for over 4 mo.

Birth weight positively predicts postnatal growth and performance in pigs and can be increased by sustained maternal porcine ST (pST) treatment from d 25 to 100 of pregnancy (term ~115 d). The objective of this study was to test whether a shorter period of maternal pST treatment in late pregnancy (d 75 to 100) could also increase birth and weaning weights of progeny under commercial conditions. Gilts (parity 0) and sows (parities 2 and 3) were not injected (controls) or injected daily with pST (gilts: 2.5 mg•d^-1, sows: 4.0 mg•d^-1, both ~13 to 14 μg•kg^-1•d^-1) from d 75 to 100 of pregnancy. Litter size and BW were recorded at birth and weaning, and dams were followed through the subsequent mating and pregnancy. Maternal pST injections from d 75 to 100 increased litter average progeny weight at birth (+96 g, P = 0.034) and weaning (+430 g, P = 0.038) in sows, but had no effect on progeny weight in gilts (each P > 0.5). Maternal pST treatment did not affect numbers of live-born piglets and increased numbers of still-born piglets in sows only (+0.4 pigs/litter, P = 0.034). Maternal pST treatment did not affect subsequent reproduction of dams. Together with our previous data, these results suggest that sustained increases in maternal pST are required to increase fetal and postnatal growth in gilt progeny, but that increasing maternal pST in late pregnancy only may be an effective strategy to increase fetal and possibly postnatal growth in sow progeny.

The objectives of this study were to determine the effects of supplementation with a single or sequence of β-adrenergic agonists (β-AA) on cow performance, carcass characteristics, and mRNA relative abundance of cull cows implanted and fed a concentrate diet. Sixty cull cows were implanted with Revalor-200 (200 mg trenbolone acetate and 20 mg estradiaol) and assigned to 1 of 4 treatments (n = 15/treatment): C = fed a concentrate diet only; RH = supplemented with ractopamine-HCl (RH) for the last 25 d before harvest; ZH = supplemented with zilpaterol-HCl (ZH) for 20 d prior to a 3 d withdrawal before harvest; RH + ZH = supplemented with RH for 25 d followed by ZH for 20 d prior to a 3 d withdrawal before harvest. Ractopamine-HCl was supplemented at a dose of 200 mg·head-1·d-1 and ZH was supplemented at 8.33 mg/kg (100% DM basis) of feed. All cows were fed a concentrate diet for 74 d. Each treatment had five cows per pen and three replicate pens. On d 1, 24, 51, and 72, BW were collected. Muscle biopsies from the LM were collected on d 24, 51, and at harvest from a subsample of three cows per pen. Carcass traits were evaluated postharvest. The two ZH treatments averaged 15.3 kg more weight gain, 0.20 kg higher ADG, and 7.8 cm² larger LMA than C and RH treatments, and 21 kg more HCW than C but these differences were not significant (P > 0.10) likely due to sample size of n = 15/treatment. The sequence of RH followed by ZH tended to optimize the combination of HCW, LMA, % intramuscular fat, and lean color and maturity compared to the ZH treatment. Abundance of β₂-adrenergic receptor (AR) mRNA was not altered in the RH + ZH treatment during RH supplementation from d 24 to 51 of feeding. However, the abundance of β₂-AR mRNA increased (P < 0.05) the last 23 d of feeding for the RH treatment and tended (P = 0.10) to increase in ZH cows during ZH supplementation. For all cows, abundance of Type IIa myosin heavy chain (MHC-IIa) mRNA decreased (P < 0.05) after 24 d of feeding. Abundance of MHC-IIx mRNA increased (P < 0.05) for ZH and RH + ZH treatments the last 23 d of feeding during ZH supplementation. Although few significant differences were observed in performance or carcass traits, mRNA quantification indicated that β-AA supplementation elicited a cellular response in cull cows. Economically, implanting and feeding cull cows for 74 d, regardless of β-AA supplementation, added value by transitioning cows from a "cull" cow to what industry refers to as a "white" cow market in which cows have white fat resulting from grain feeding.

This study investigated the effects of a mixed bacterial inoculant possessing ferulic acid esterase (FAE) activity on silage fermentation characteristics, aerobic stability and growth performance of growing feedlot steers. Whole-crop barley (Hordeum vulgare, L.) forage (35% DM) was chopped and ensiled without a silage inoculant (UN) or with a mixed bacterial culture containing 1.0 x 10¹¹ cfu g^-1 of Lactobacillus buchneri LN4017 that produces FAE, 2.0 x 10¹⁰ cfu g^-1 of Lactobacillus plantarum LP7109 and 1.0 x 10¹⁰ cfu g^-1 of Lactobacillus casei LC3200 at a combined rate of 1.3 x 10⁵ cfu g^-1 of fresh forage (IN) in mini and Ag-Bag silos. Silages from the mini silos were assessed for the effect of inoculation on fermentation characteristics and aerobic stability whereas those from Ag-Bags were used to formulate two barley silage-based TMR (UN and IN) that were fed to growing feedlot steers for 112 d. The IN silage exhibited a homolatic fermentation during the first 7 d of ensiling as reflected by an increased (P ≤ 0.02) lactic acid concentration and an accelerated rate (P < 0.01) of pH decline. Thereafter, fermentation of IN silage became more heterolactic resulting in higher concentrations of acetic acid (P < 0.01) and pH (P < 0.01), but lower (P < 0.01) lactic acid than UN silage. Inoculation did not affect DM losses (P = 0.52) from mini-silos. The IN silage remained stable during 21-d, but temperature and yeasts counts in the UN silage increased after 5 d of aerobic exposure. Growing steers fed the IN silage diet had superior (P = 0.03) feed conversion efficiency as compared to those fed UN silage. Inoculation of whole-crop barley silage with a mixed culture of homolactic LAB and FAE-producing L. buchneri at ensiling changed fermentation from a homolactic to a heterolactic form during ensiling and improved aerobic stability of the silage and efficiency of gain of growing feedlot steers.

The present study was conducted to (1) identify the natural source of feed contamination by zearalenone (ZEN), which was suspected to have caused persistently high urinary ZEN concentrations in one of our experimental cattle herds, and (2) evaluate the effects of intervention against this source of contamination. As an experimental model, a fattening Japanese Black cattle herd showing persistently high urinary ZEN concentrations was identified. Urinary ZEN concentrations of cows fed with new rice straw (experimental group, n = 6) versus cows that continued to feed on the old rice straw (control group, n = 4) were measured at the start (d 1) and at 2 wk (d 14) after the onset of feeding with straw. In addition, the ZEN concentration in feed and water samples was measured by using both the ELISA and HPLC methods. Furthermore, isolation and identification of fungi from rice straw and concentrate feed samples were performed. The urinary ZEN concentration (ZEN [pg/mL]/creatinine (Crea) [mg/mL] = pg/mg of Crea) of cows fed with new rice straw was significantly (P < 0.05) lower (843 pg/mg of Crea) than that of cows fed with old rice straw (15,951 pg/mg of Crea). On both d 1 and 14, the ZEN concentrations of old rice straw were higher than those of new rice straw. In addition, fungal colonies were observed in the culture media that was obtained from the old rice straw suspected of ZEN contamination, but not in the culture media from new rice straw or other feed samples. In conclusion, our field trials clearly indicate that the rice straw fed to the cows was naturally contaminated with ZEN, and that the monitoring of urinary ZEN concentrations could prove to be a useful tool for detecting the exposure of cattle to ZEN contamination at the farm level.

The objectives of this study were to determine the effects of 0, 20, 40 or 60% dietary dried distillers grains with solubles (DDGS) on: (1) growing lamb performance, carcass characteristics, and tissue minerals, and (2) nutrient digestibility and retention in growing lambs. Exp. 1: Ninety-six lambs were blocked by sex (ewes, n = 48; wethers, n = 48) and weight, housed in 24 pens (4 lambs per pen), and used in a 92 d feedlot trial (initial BW = 26.4 ± 9.3 kg). Lambs were fed 1 of 4 dietary treatments: 1) 0% DDGS, 2) 20% DDGS, 3) 40% DDGS, or 4) 60% DDGS. The DDGS replaced primarily corn, and diets were fed as a complete pellet. There was a quadratic effect of DDGS inclusion on ADG; lambs fed the 20% DDGS diet had the greatest (P = 0.04) gains at 0.358 kg/d. This effect on ADG led to a quadratic (P = 0.03) effect of DDGS on final BW. Increasing dietary DDGS did not affect (P > 0.13) DMI and resulted in a linear (P = 0.02) decrease in G:F. In the liver, S increased linearly (P = 0.05) while Cu decreased linearly (P < 0.01) with increasing dietary DDGS; other liver minerals were not affected (P > 0.05). Carcass back fat, yield grade, and marbling score were not affected (P > 0.05) by dietary DDGS. Exp. 2: Twenty-four lambs (initial BW = 43.0 ± 4.4 kg) were used in a metabolism study. Lambs were adapted to the same diets described above for 17 d before a 5 d sampling period during which total feces and urine were collected. Apparent digestibility of dietary DM decreased linearly (P < 0.01) with increasing dietary inclusion of DDGS. Digestibility of fat followed a similar pattern, whereas, N, S, and P absorption increased linearly (P < 0.03) with increasing dietary DDGS. The digestibility of NDF was not affected (P > 0.05) by dietary treatment. Apparent retentions (as a percentage of intake) of N, K, Mg, Cu, Fe, and Zn, were not affected (P > 0.05) by dietary DDGS inclusion while the retention of S and P decreased (P < 0.04). Daily urine output increased linearly (P < 0.01) and urine pH decreased linearly (P < 0.01) with increasing DDGS (urine pH was 7.46, 5.86, 5.52 and 5.32 for treatments 1 to 4, respectively). These data suggest urine is a major route for excretion of acid when high S diets containing DDGS are fed. Increases in dietary DDGS resulted in decreased digestion of DM and fat which may be partially responsible for decreased lamb feedlot performance for 40 and 60% dietary DDGS when compared to 20% DDGS.

Quantification of the pro-vitamin A carotenoids in feedstuffs commonly fed to livestock has been ignored for many years. A high dietary concentration of vitamin A has the potential to limit adipogenesis in cattle, therefore reducing carcass quality and value. A survey of 18 feedstuffs commonly fed to beef cattle was conducted for determination of vitamin A equivalents based on analysis of carotenoids. The pro-vitamin A carotenoids of interest were β- and α-carotene, and β-cryptoxanthin. Collaborators in 5 states collected the feedstuffs and then shipped them to The Ohio State University for compilation and analysis. Carotenoids were extracted from the feedstuffs and then quantified using HPLC with photodiode array analysis. Fresh fescue pasture contained approximately 10 times more vitamin A equivalents than hay and 5 times more than corn silage (39,865, 2,750, and 6,900 IU vitamin A/kg DM for fresh pasture, hay, and corn silage, respectively). β-cryptoxanthin and α-carotene could not be detected in any forage samples. Hay and corn silage vitamin A equivalents decreased over extended periods of time from harvest to sample collection. Corn was the only feedstuff to have appreciable concentrations of all 3 pro-vitamin A carotenoids quantified. Corn processing had minimal impact on the vitamin A equivalents. High moisture corn contained 54% more vitamin A equivalents than whole shelled corn (378 and 174 IU vitamin A /kg DM, respectively). Pro-vitamin A carotenoids were more concentrated in corn co-products than whole shelled corn. The drying of distillers grains with solubles may significantly degrade β-carotene (800 and 480 IU /kg DM for wet and dry distillers grains, respectively). Soybean based feedstuffs contain a small concentration of pro-vitamin A carotenoids, at 55 and 45 IU vitamin A /kg DM for soybean meal and soyhulls, respectively. Overall, there was considerable variation in the pro-vitamin A content of feedstuffs based on location and storage conditions. An extensive analysis of feedstuffs would need to be conducted to accurately estimate the vitamin A content of feedlot cattle diets.

The relationship between barometric pressure (BARO) and maximum (MAX_T) and minimum (MIN_T) environmental temperatures with the incidence of parturition in beef cows was examined through exploratory data analysis. Spring- and fall-calving records from a 5-yr period (2005 through 2009) collected at the University of Arkansas, Livestock and Forestry Research Station (Batesville, AR) and Department of Animal Science Savoy Research Unit (Savoy, AR) were used. All cows were multiparous, predominately Angus, and naturally bred. During this period, 2,210 calves were born over a cumulative 1,547 d. Local weather station BARO and MAX_T and MIN_T data were obtained from the Southern Regional Climate Center, Louisiana State University, Baton Rouge, LA. The combined calving record and climate variables were used to determine differences in BARO, MAX_T, and MIN_T on d 0 (d of calving) and -1, -2, or -3 (d before calving, respectively) calving occurred (CALF) or did not occur (NOCALF). Location and season also were included in the model. For fall-calving cows, BARO on d 0 and -1, -2, or -3 was not different between CALF and NOCALF (P > 0.10). For spring-calving cows, BARO on d 0, -1, -2, and -3 was greater (P < 0.05) for CALF compared with NOCALF. The MAX_T was greater on d -1 (24.4° vs. 22.9°C) and -3 (24.8° vs. 23.4°C) for CALF in the fall compared with NOCALF (P < 0.05). No differences were detected in the fall for MAX_T on d 0 or -2 (P > 0.10). In the spring, lesser MAX_T was associated with CALF. Maximum environmental temperatures on d 0 (14.7° vs. 16.0°C), -1 (14.4° vs. 16.0°C), and -3 (14.0° vs. 15.7°C), were lesser for CALF compared with NOCALF (P < 0.05). No difference was detected on d -2 (P > 0.10). For fall, MIN_T was greater on d -1 (12.8° vs. 11.3°C), -2 (13.0° vs. 11.4°C), and -3 (13.1° vs. 11.7°C) for CALF compared with NOCALF (P < 0.05). In spring, MIN_T for d 0 (2.6° vs. 3.9°C), -1 (2.5° vs. 3.7°C), -2 (2.1° vs. 3.7°C), and -3 (1.8° vs. 3.8°C) were lesser (P < 0.05) for CALF verses NOCALF. These data indicate for spring-calving cows, a higher BARO and decrease in MAX_T and MIN_T was associated with CALF; whereas, for fall-calving cows an increase in MAX_T and MIN_T was associated with CALF. Therefore, monitoring weather conditions may assist producers in preparing for the obstetric assistance of beef cattle.

Data on associations between weather conditions and bovine respiratory disease (BRD) morbidity in autumn-placed feedlot cattle are sparse. The goal of our study was to quantify how different weather variables during corresponding lag periods (considering up to seven days prior to the day of disease measure) were associated with daily BRD incidence during the first 45 d of the feeding period based on a post-hoc analysis of existing feedlot operational data. Our study population included 1,904 cohorts of feeder cattle (representing 288,388 total cattle) that arrived to nine U.S. commercial feedlots during September to November in 2005 to 2007. There were 24,947 total cases of initial respiratory disease (animals diagnosed by the feedlots with BRD and subsequently treated with an antimicrobial). The mean number of BRD cases during the study period (the first 45 d after arrival) was 0.3 cases/d/cohort (range = 0 to 53.0) and cumulative BRD incidence risks ranged from 0 to 36% within cattle cohorts. Data were analyzed with a multivariable mixed-effects binomial regression model. Results indicate that several weather factors (maximum wind speed, mean wind chill temperature, and temperature change in different lag periods) were significantly (P < 0.05) associated with increased daily BRD incidence, but their effects depended on several cattle demographic factors (month of arrival, BRD risk code, weight class and cohort size). In addition, month and year of arrival, gender of the cohort, days on feed, cohort’s mean weight at entry, predicted BRD risk designation of the cohort (high or low risk), cohort size and the interactions between BRD risk code and arrival year were significantly (P < 0.05) associated with daily BRD incidence. Our results demonstrate the weather conditions that are significantly associated with BRD risk in populations of feedlot cattle. Defining these conditions for specific cattle populations may enable cattle health managers to predict and potentially manage these effects more effectively; further, estimates of effects may contribute to the development of quantitative predictive models for this important disease syndrome.

Supplementation of vitamin E has indications for improving cattle health, performance, and retail characteristics when included in grain-based diets. This experiment was conducted to determine performance and carcass characteristics of steers fed diets containing wet distillers grains with solubles (WDGS) and supplemented with vitamin E. Steers of mixed Bos indicus and Bos taurus breeding (n = 199; BW = 363 ± 32 kg) were blocked by BW and assigned to 1 of 4 supplemental vitamin E (VITE) treatment levels (0 [Control], 125, 250, and 500 IU·steer^-1·day^-1), which was fed for the last 97 d of the feeding period. Two blocks were on feed 129 d and 3 blocks were fed for 150 d. Steers were fed a dry-rolled corn-based finishing diet with 35% WDGS (DM basis). Individual BW were measured initially, the initial day of vitamin E supplementation, and the day of harvest. Carcass weights were collected at harvest, and carcass data were collected after a 36-h chill. Live BW and ADG were not affected by VITE (P ≥ 0.34). There was a tendency for a linear (P = 0.08) increase in carcass adjusted BW with increasing VITE. Use of carcass adjusted final BW resulted in a linear increase (P = 0.04) in ADG with increasing VITE. Pre-vitamin E and vitamin E feeding period DMI were not affected (P ≥ 0.24) by VITE, but there was a tendency (P = 0.08) for a linear increase in overall DMI with increasing VITE. No difference (P ≥ 0.29) occurred in G:F measures using live weight gains, but G:F using carcass adjusted weight gains resulted in a trend (P = 0.11) for G:F to increase linearly with increasing VITE. Hot carcass weights tended (P = 0.08) to increase linearly with increasing dietary vitamin E. Vitamin E supplementation resulted in no effects (P ≥ 0.13) on measured carcass characteristics. Calculated yield grades (YG) were also not affected (P ≥ 0.37). However, the distribution of calculated YG resulted in a quadratic effect (P = 0.02) for YG 3 with the Control and 500 VITE being greater than the 2 intermediate levels. However, the percentage of carcasses grading YG 3 or lower were not affected by vitamin E supplementation (P = 0.64). No differences were observed in the distribution of quality grades based on marbling scores (P ≥ 0.57). Data from this study suggest that vitamin E supplemented above basal requirements during the last 97 d of the feeding period in finishing diets containing 35% WDGS results in slight to no impact on animal performance or carcass characteristics.

The goal of this research was to develop empirical equations to predict chemical and physical compositions of the carcass and the body using the composition of the 9-11^th rib section (Rib_9-11) and other measurements. A database (n = 246) from 6 studies was developed and comprised of 37 bulls (BU), 115 steers (ST), and 94 heifers (HF) of which 132 were Nellore (NE), 76 were NE x Angus crossbreds (NA), and 38 were NE x Simmental crossbreds (NS). The right half carcass and the Rib_9-11 from the left half carcass were analyzed for ether extract (EE), CP, and water. The remaining components were chemically analyzed to determine the composition of the body. A stepwise procedure was used to determine the variable inclusion in the regression models. The variables included were EE in the Rib_9-11 (EER, %), CP in the Rib_9-11 (CPR, %), water in the Rib_9-11 (WR, %), visceral fat (pelvic, kidney, heart, and mesenteric fats; VF, %), organs plus viscera (OV, %), carcass dressing percentage (CD, %), cold carcass weight (CCW, kg), and empty BW (EBW, kg). There were no sex or breed effects on EE and CP compositions of the carcass (C_EE and C_CP, %, respectively) and the equations were: C_EE = 4.31 + 0.31xEER + 1.37xVF [n = 241, R² = 0.83, mean square error (MSE) = 4.53] and C_CP = 17.92 + 0.60xCPR – 0.17xCD (n = 238, R² =0.50, MSE=1.58). On the other hand, breed affected water content in the carcass (C_W, %) and the equations were: C_W = 48.74 + 0.28xWR – 0.017xEBW for NE; C_W = 46.69 + 0.32xWR – 0.017xEBW for NA; and C_W = 38.06 + 0.48xWR – 0.017xEBW for NS (n = 243, R² =0.67, MSE = 5.17). There was a sex effect on body chemical EE composition (BW_EE) (BW_EE = 2.75 + 0.33xEER + 1.80xVF for BU; BW_EE = 1.84 + 0.33xEER + 1.91xVF for ST; and BW_EE = 4.77 + 0.33xEER + 1.28xVF for HF (n = 243, R² = 0.89, MSE = 3.88). There were no sex or breed effects on CP composition in the body (BW_CP) (BW_CP = 14.38 + 0.24xCPR; n = 240, R² = 0.59, MSE=1.06). There was a sex effect for body water content (BW_W) and the equations were: BW_W = 38.31 + 0.33xWR – 1.09xVF + 0.50xOV for BU; BW_W = 45.67 + 0.25xWR – 1.89xVF + 0.50xOV for ST; and BW_W = 31.61 + 0.47xWR – 1.06xVF + 0.50xOV for HF (n = 241, R² = 0.81, MSE = 3.84). The physical carcass composition indicated a breed effect on all components and a sex effect for fat in the carcass. We concluded that body and carcass compositions can be estimated with Rib_9-11 for purebred and crossbred NE animals, but specific equations have to be developed for different groups of animals.

Ergovaline has been extensively used to study vasoactive effects of endophyte- (Neotyphodium coenophialum) infected tall fescue (Lolium arundinaceum). However, initial results indicated that an extract of toxic tall fescue seed (E+EXT) is more potent than ergovaline alone in a right ruminal artery and vein bioassay. The E+EXT induced a greater contractile response than an equal concentration of ergovaline alone in the ruminal artery of heifers (P = 0.018). This led to a hypothesis that other compounds in the seed extract contribute to vasoconstriction. Thus, experiments were conducted to determine if vasoactivity of an E+EXT is different from a mixture of ergot alkaloids (ALK; ergovaline, ergotamine, ergocristine, ergocryptine, ergocornine, ergonovine, and lysergic acid) of similar concentrations and to determine if the vasoactivity of an E+EXT differs from an endophyte-free tall fescue seed extract (E-EXT). Segments of lateral saphenous vein and right ruminal artery and vein were collected from Holstein steers (n = 6) shortly after slaughter. Vessels were cleaned of excess connective tissue and fat and sliced into segments that were suspended in a multi-myograph chamber with 5 mL of continually-oxygenated Krebs-Henseleit buffer, equilibrated for 90 min, and exposed to a reference compound (120 mM KCl for ruminal vessels and 0.1 mM norepinephrine for saphenous vein). Increasing concentrations of each treatment (E+EXT, E-EXT, ALK, and ergovaline) were added to the respective chamber every 15 min following buffer replacement. Data were normalized as a percentage of maximal contractile response of the reference compound and fit to a sigmoidal concentration response curve. Ergovaline, ALK, and E+EXT induced similar responses in the saphenous vein, ruminal artery, and ruminal vein. The E+EXT displayed a smaller EC₅₀ than ergovaline or ALK in the saphenous vein and ruminal vein (P < 0.008) but not ruminal artery (P = 0.31). Extrapolated maximum response (E_max) was greatest in the saphenous vein for ergovaline, lowest for E+EXT, and intermediate for ALK (P < 0.0001). The E-EXT did not induce a contractile response in any vessel tested (P > 0.1). Data from this study indicate that ergovaline is largely responsible for the locally induced vasoconstriction of bovine vasculature observed with endophyte- infected tall fescue.

An experiment was conducted to test the hypothesis that the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P in fermented soybean meal (FSBM) are greater than conventional soybean meal (SBM-CV) when fed to growing pigs. Four diets were formulated to contain FSBM or SBM-CV and either 0 or 800 units/kg of microbial phytase . The only sources of P in these diets were FSBM and SBM-CV. A P-free diet to estimate basal endogenous losses of P was also formulated. Thirty barrows (initial BW: 14.0 ± 2.3 kg) were placed in metabolism cages and allotted to 5 diets in a randomized complete block design with 6 pigs per diet. Feces were collected for 5 d after a 5-d adaptation period. All samples of ingredients, diets, and feces were analyzed for P and values for ATTD and STTD of P were calculated. Results indicated that the basal endogenous P losses were 187 mg/kg DMI. As phytase was added to the diet, the ATTD and STTD of P increased (P < 0.01) from 60.9 to 67.5% and from 65.5 to 71.9%, respectively, in pigs fed FSMB. Likewise, addition of phytase to SBM-CV increased (P < 0.01) the ATTD and STTD of P from 41.6 to 66.2% and from 46.1 to 71.4%, respectively. The ATTD and STTD of P were greater (P < 0.01) in FSBM than in SBM-CV when no phytase was used, but that was not observed when phytase was added to the diet (soybean meal x phytase interaction, P < 0.01). In conclusion, the ATTD and STTD of P in FSBM was greater than SBM-CV when no microbial phytase was addedd, but, when phytase was added to the diets, no differences in ATTD and STTD of P between FSBM and SBM-CV are observed.

Ammonia (NH₃) can accumulate in highly stocked sheep accommodation, for example during live export shipments, and could potentially impact sheep health and welfare. Thus the objective of this experiment was to test the effects of 4 NH₃ concentrations, 4 (control), 12, 21 and 34 mg/m³, on the physiology and behavior of wether sheep. Sheep were held for 12 d under a micro-climate and stocking density similar to shipboard conditions recorded on voyages from Australia to the Middle East during the northern hemispheric summer. Ammonia increased macrophage activity in transtracheal aspirations, indicating active pulmonary inflammation; however, it had no effect (P > 0.05) on hematological parameters. Feed intake reduced (P = 0.002) in proportion to ammonia concentration, and liveweight gain reduced (P < 0.001) at the 2 highest concentrations. Exposure to ammonia increased (P = 0.03) the frequency of sneezing, and at the highest ammonia concentration, sheep were less active, with less locomotion, pawing and panting. Twenty-eight days after exposure to NH₃, the sheep’s pulmonary macrophage activity and live weight returned to that of sheep exposed to only 4 mg/m³. It was concluded that NH₃ induced a temporary inflammatory response of the respiratory system and reduced weight gain, which together indicated a transitory adverse effect on the welfare of sheep.

The influence of dietary nutrient concentration on growth performance, manure composition, and gas emission was studied in pigs in hot environmental conditions. A total of 64 intact males and 64 females [(Landrace x Large White) x Pietrain] weighing 63.1 ± 9.7 kg were divided into 2 dietary treatments: high (HD: 14.39 MJ DE/kg and 1.11% Lys) and low (LD: 13.97 MJ DE/kg and 1.01% Lys) in energy and Lys contents. Pigs were allocated to 32 split sex pens with 4 pigs/pen and 16 pens/treatment. Average productive performance was recorded for 41 d (phase 1). After phase 1, 12 females of 103.3 ± 3.15 kg (6 per treatment) were selected and housed individually and feces and slurry were collected during 3 and 4 consecutive days, respectively, to calculate nutrient digestibility and measure gas emissions (phase 2). For gas emission measurements, slurry was pooled by treatment and stored for 76 d. Initial composition of slurry and pH were analyzed. Maximum and minimum temperatures registered in the barn throughout the growing period where 35.1 and 18.1ºC, respectively. Animals fed the HD diet grew more efficiently than pigs fed the LD diet (G:F, 0.43 vs. 0.40; SEM = 0.01; P < 0.05). Fat digestibility was higher in HD compared to LD pigs (88.0 vs. 84.9%; SEM = 0.9; P < 0.05). Slurry from pigs fed the LD diet showed greater DM, OM, total N, and VFA contents than slurry from pigs fed the HD diet. Cumulative NH₃, CO₂, and especially CH₄ emissions were greater in the HD slurry compared to the LD slurry (192,4 vs. 210,4 g NH₃/m³; 2,712 vs. 3,210 g CO₂/m³; 1,502 vs. 2,647 mL CH₄/kg OM). Increasing feed density in the present study led to a more efficient growth, a lower nutrient concentration in the slurry, and a greater gas emission.

Two experiments were conducted to determine the requirement of available P (aP) of pigs selected for high lean deposition during summer (maximum and minimum temperatures of 29.8 ± 3.6 and 21.3 ± 1.1ºC, respectively; Exp. 1) and winter (maximum and minimum temperatures of 24.7 ± 2.1 and 9.1 ± 1.6ºC, respectively; Exp.2). Pigs (66.5 ± 2.8 kg, Exp. 1; and 61.1 ± 0.6 kg, Exp. 2) were randomly allotted to 5 dietary treatments. Exp. 1 had 5 pens/treatment and Exp. 2 had 6 pens/treatment and all pens had 2 pigs. Treatments were composed of a corn-soybean meal basal diet and 4 diets with additional dicalcium phosphate to obtain 5 aP concentrations (0.122, 0.187, 0.252, 0.317, and 0.382% in Exp. 1, and 0.135, 0.200, 0.265, 0.330, and 0.395% in Exp. 2). Pigs were allowed ad libitum access to their respective diets for 30 d. In Exp. 1, increasing aP improved ADFI and ADG (quadratic, P < 0.05), with maximum responses obtained at 0.226 and 0.256% of aP, respectively. Increasing aP improved (P < 0.05) G:F. A broken-line analysis indicated that G:F was maximized (P < 0.05) at 0.295% of aP or 9.04 g aP/d. Increasing aP also increased (quadratic, P < 0.05) P and Ca (g/kg) in the metacarpals with maximum responses obtained at 0.314 and 0.272% of aP, respectively. The percentage of ash in the metacarpals continued to increase (linear, P < 0.05) with increasing aP. In Exp. 2, ADG and G:F improved (linear and quadratic, P < 0.05) as aP increased in the diet. A broken-line analysis indicated that G:F was maximized (P < 0.05) at 0.316% of aP or 10.58 g aP per d. However, increasing aP had no effect on ADFI. Percentages of ash, P, and Ca in the metacarpals increased (linear, P < 0.05) with increasing aP. In conclusion, results of this experiment indicated that finishing pigs (60 to 100 kg) kept at thermoneutral environment require 0.316% aP in the diet (10.58 g/d) to maximize G:F, but the requirement is only 0.295% aP (9.04 g/d) when pigs are under heat stress.

The aim of the present study was to investigate the influence of feeding rumen-protected CLA during the early growing period on physical and chemical beef properties in young Simmental heifers. Thirty six 5 months old heifers (initial BW 185 ± 21 kg) were allotted to three treatment groups and fed daily 250 g of different rumen-protected fats for 16 weeks: The control group received 250 g of a CLA-free control fat, the CLA100 group received 100 g of a CLA fat containing 2.4% of cis-9, trans-11 CLA and 2.1% of trans-10, cis-12 CLA and 150 g control fat, and the CLA250 group received 250 g of the CLA fat. Heifer growth performance parameters as well as carcass weight, classification (conformation and fatness), and weights of organs and fat depots were not affected (P > 0.05) by CLA supplementation. Concentration of trans-10, cis-12 CLA in tissues (LM and subcutaneous fat) was dose-dependently increased (P < 0.01) by CLA supplementation, whereas that of cis-9, trans-11 CLA in these tissues did not differ (P > 0.05) between groups. The ratio of saturated to monounsaturated fatty acids was increased (P < 0.01) in tissues of CLA fed heifers compared to control heifers. Concentration of α-tocopherol in LM was greater (P = 0.01) in heifers of the two CLA groups than in control heifers. Other quality characteristics such as drip loss during storage, cooking loss, intramuscular fat content, and color parameters in LM did not differ (P > 0.05) between groups. In conclusion, the present study demonstrates that feeding of rumen-protected CLA during the early growing period changes tissue fatty acid composition, but does not influence beef quality parameters. Performance parameters and carcass traits in young heifers, unlike in pigs and laboratory animals, are not influenced by CLA feeding.

The aim of the study was to determine the effects of three feeding dose-programs of the β-adrenergic agonists (β-AA) ractopamine hydrochloride (RH) or zilpaterol hydrochloride (ZH) for the final 30 d before harvest, on growth performance, carcass and meat characteristics of feedlot ram lambs. Eighty-four Dorper x Katahdin ram lambs (30.0 ± 1.6 kg) were blocked by weight and randomly assigned to pens (four lambs per pen and three pens per treatment). Pens within a block were assigned randomly to 1 of 7 dietary treatments: 1) control (CTL) = diet without β-AA; 2) RH constant (RHC) = 20.0 mg/kg RH, d 1 to 30; 3) RH increasing (RHI) = 10.0 mg/kg, d 1 to 10; 20.0 mg/kg, d 11 to 20; and 30.0 mg/kg, d 21 to 30; 4) RH decreasing (RHD) = 30.0 mg/kg, d 1 to 10; 20.0 mg/kg, d 11 to 20; and 10.0 mg/kg, d 21 to 30; 5) ZH constant (ZHC) = 6.0 mg/kg ZH, d 1 to 30; 6) ZH increasing (ZHI) = 3.0 mg/kg, d 1 to 10; 6.0 mg/kg, d 11 to 20; and 9.0 mg/kg d 21 to 30; and 7) ZH decreasing (ZHD) = 9.0 mg/kg, d 1 to 10; 6.0 mg/kg, d 11 to 20; and 3.0 mg/kg, d 21 to 30. Overall, β-AA supplementation reduced DMI (P < 0.001) as compared to CTL lambs, but lambs fed RHI and ZHI programs had greater (P < 0.05) total weight gain, ADG and G:F. Carcass weight was improved (P < 0.05) by RHI and ZHI programs, but dressing percentage was enhanced (P < 0.05) by only ZHC or ZHI treatments. Fat thickness and yield grade were reduced (P < 0.05) by ZH or RH regardless of feeding program. Most LM characteristics (pH, moisture loss, and chemical composition) were not different among treatments (P > 0.05), with exception of fat content that was reduced (P < 0.001) in lambs fed β-AA, and diameter of muscle fibers that were increased (P < 0.05) by ZHI treatment. Constant and increasing doses of ZH reduced (P < 0.05) the a* value of LM and semitendinosus (ST) muscles, with no effects on L* or b* values. The mass of liver was reduced (P < 0.05) in ZHI treated lambs as compared to CTL lambs, and plasma urea concentration was reduced (P < 0.05) by RH or ZH administration regardless of feeding program; although, there were no other differences in organ mass weight (P ≥ 0.35) or blood metabolites (P ≥ 0.16). Increasing doses of RH or ZH augmented the growth performance response without negative effects on organ mass weight or blood metabolites. Although, a ZHI program improved carcass characteristics, the increased LM fiber diameter of lambs fed ZHI program could be unfavorable due to the potential negative effect on tenderness.

Twenty corn co-products from various wet- and dry-grind ethanol plants were fed to finishing pigs to determine DE and ME, and to generate equations predicting DE and ME based on chemical analysis. A basal diet was composed of corn (97.05%), limestone, dicalcium phosphate, salt, vitamins, and trace minerals. Twenty test diets were formulated by mixing the basal diet with 30% of a co-product, except for dried corn solubles and corn oil, which were included at 20 and 10%, respectively. There were 8 groups of 24 finishing gilts (n = 192; BW = 112.7 ± 7.9 kg). Within each group, gilts were randomly assigned to 1 of 5 test diets or the basal diet for a total of 4 replications per diet per group. Two groups of gilts were used for each set of co-products, resulting in 8 replications per co-product and 32 replications of the basal diet. The experiment was conducted as a completely randomized design. Gilts were placed in metabolism crates and offered 3 kg daily of their assigned test diet for 13 d with total collection of feces and urine during the last 4 d. Ingredients were analyzed for DM, GE, CP, ether extract (EE), crude fiber, NDF, ADF, total dietary fiber (TDF), ash, AA, and minerals, and in vitro OM digestibility was calculated for each ingredient. Gross energy was determined in the diets, feces, and urine to calculate DE and ME for each ingredient. The DE and ME of the basal diet were used as covariates among groups of pigs. The DE of the co-products ranged from 2,517 kcal/kg DM (corn gluten feed) to 8,988 kcal/kg DM (corn oil), and ME ranged from 2,334 kcal/kg DM (corn gluten feed) to 8,755 (corn oil) kcal/kg DM. By excluding corn oil and corn starch from the stepwise regression analysis, a series of DE and ME prediction equations were generated. The best fit equations were: DE, kcal/kg DM = -7,471 + (1.94 x GE) – (50.91 x EE) + (15.20 x total starch) + (18.04 x OM digestibility) with R² = 0.90, SD = 227, and P < 0.01; and ME, kcal/kg DM = (0.90 x GE) – (29.95 x TDF) with R² = 0.72, SE = 323, and P < 0.01. Additional equations for DE and ME included NDF in the instance that TDF data are not available. These results indicate that DE and ME varied substantially among corn co-products, and that various nutritional components can be used to accurately predict DE and ME in corn co-products for finishing pigs.

Twenty crossbred yearling steers (421 kg) were used to evaluate the effects of implanting with trenbolone acetate (TBA; 120 mg), estradiol-17β (E₂; 25.7 mg), and the combination (120 mg TBA and 24 mg E₂) on adipogenic and myogenic mRNA concentrations. Animals were blocked by BW, and within each block, assigned to 1 of 4 treatments. Animals were housed and fed in individual pens with 5 animals per treatment. All animals were weighed weekly, and muscle biopsy samples were taken from the LM of each steer on d 0 (prior to implantation), d 7, d 14, and d 28. Total RNA was isolated from each sample and real-time quantitative PCR was used to measure the quantity of C/EBPβ, PPAR, stearoyl CoA desaturase (SCD), myogenin, and 3 isoforms of bovine myosin heavy chain (MHC) mRNA. Total BW gain from the 28-d period was adjusted to d 0 by use of covariant analysis, and implant group tended (P = 0.09) to increase BW gain over non-implanted control (CON) steers. Analysis of the gene expression of MHC showed that neither implant nor day (P > 0.20) had a significant effect on the expression of type-I or -IIX MHC mRNA There was also no treatment effect on MHC-IIA and myogenin, but increasing days on feed increased (P = 0.05) the expression of MHC-IIA mRNA. Relative mRNA levels of C/EBPβ, PPAR, and SCD increased (P < 0.05) during days of feed but PPAR decreased (P < 0.05) with the treatment of combined TBA/E₂ implant. Results of this study indicate that implanting with TBA, E₂, or both increased BW gain and decreased adipogenic gene expression of finishing steers without significantly affecting the concentration of type-I, -IIA, or -IIX MHC mRNA. Increasing days on feed increased both the levels of MHC-IIA and adipogenic gene expression in bovine skeletal muscle biopsy samples. We conclude that administration of steroidal implants had no effect on the proportion of the 3 different MHC mRNA isoforms but decreased C/EBPβ, PPAR, and SCD mRNA in bovine skeletal muscle.

Growth hormone is a major stimulator of skeletal muscle growth in animals, including cattle. In this study, we determined whether GH stimulates skeletal muscle growth in cattle by direct stimulation of proliferation or fusion of myoblasts, by direct stimulation of protein synthesis, or by direct inhibition of protein degradation in myotubes. We also determined whether these direct effects of GH are mediated by IGF-I produced by myoblasts or myotubes. Satellite cells were isolated from cattle skeletal muscle and were allowed to proliferate as myoblasts or induced to fuse into myotubes in culture. Growth hormone at 10 and 100 ng/mL increased protein synthesis in myotubes (P < 0.05), but had no effect on protein degradation in myotubes or proliferation of myoblasts (P > 0.05). Insulin like growth factor I at 50 and 500 ng/mL stimulated protein synthesis (P < 0.01), and this effect of IGF-I was much greater than that of GH (P < 0.05). Besides stimulating protein synthesis, IGF-I at 50 and 500 ng/mL also inhibited protein degradation in myotubes (P < 0.01), and IGF-I at 500 ng/mL stimulated proliferation of myoblasts (P < 0.05). Neither GH nor IGF-I had effects on fusion of myoblasts into myotubes (P > 0.1). These data indicate that GH and IGF-I have largely different direct effects on bovine muscle cells. Growth hormone at 10 and 100 ng/mL had no effect on IGF-I mRNA expression in either myoblasts or myotubes (P > 0.1). This lack of effect was not because the cultured myoblasts or myotubes were not responsive to GH, as GHR mRNA was detectable in them and the expression of the cytokine-inducible SH2-containing protein (CISH) gene, a well-established GH target gene, was increased by GH in bovine myoblasts (P < 0.05). Overall, the data suggest that GH stimulates skeletal muscle growth in cattle in part through stimulation of protein synthesis in the muscle and that this stimulation is not mediated through increased IGF-I mRNA expression in the muscle.

The genetics of reproduction is poorly understood because the heritabilities of traits currently recorded are low. In order to elucidate the genetics underlying reproduction in beef cattle we performed a genome wide association study using the bovine SNP50 chip in two tropically adapted beef cattle breeds; Brahman and Tropical Composites. Here we present the results for three female reproduction traits: (1) Age at puberty, defined as age in days at first observed corpus luteum (CL) following frequent ovarian ultrasound scans (AGECL); (2) the post partum anoestrous interval, measured as the number of days from calving to first ovulation post partum (first re-breeding interval, PPAI) and (3) The occurrence of the first post-partum ovulation prior to weaning in the first re-breeding period (PW), defined from PPAI. In addition, correlated traits such as weight, height, serum IGF1 concentration, condition score and fatness were also examined. In the Brahman and Tropical Composite cattle, 169 (false positive rate (FPR) = 0.262) and 84 (FPR = 0.581) SNP, respectively, were significant (P < 0.001) for AGECL. In Brahman, 41% of these significant markers mapped to a single chromosomal region on BTA14. In Tropical Composites, 16% of these significant markers were located on BTA5. For PPAI, 66 (FPR = 0.67) and 113 (FPR = 0.432) SNP were significant (P < 0.001) in Brahman and Tropical Composite respectively, while for PW, 68 (FPR = 0.64) and 113 (FPR = 0.432) SNP were significant. In Tropical Composites, the largest concentration of PPAI markers were located on BTA5 (19% (PPAI) and 23% (PW)), and BTA16 (17% (PPAI) and 18% (PW)). In Brahman cattle the largest concentration of markers for post partum anoestrus was located on BTA 3 (14% for PPAI and PW) and BTA14 (17% PPAI). Very few of the significant markers for female reproduction traits for the Brahman and Tropical Composite breeds were located in the same chromosomal regions. However, fatness and live weight traits as well as serum IGF1 concentration were found to be associated with identical genome regions within and between breeds. Clusters of SNP associated with multiple traits were located on BTA14 in Brahman and BTA5 in Tropical Composites.

Modern animal breeding datasets are large and getting larger, due in part to recent availability of high-density single nucleotide polymorphism arrays and cheap sequencing technology. High-performance computing methods for efficient data warehousing and analysis are under development. Financial and security considerations are important when using shared clusters. Sound software engineering practices are needed, and it is better to use existing solutions when possible. Storage requirements for genotypes are modest, although full-sequence data will require greater storage capacity. Storage requirements for intermediate and results files for genetic evaluations are much greater, particularly when multiple runs must be stored for research and validation studies. The greatest gains in accuracy from genomic selection have been realized for traits of low heritability, and there is increasing interest in new health and management traits. The collection of sufficient phenotypes to produce accurate evaluations may take many years, and high-reliability proofs for older bulls are needed to estimate marker effects. Data mining algorithms applied to large datasets may help identify unexpected relationships in the data, and improved visualization tools will provide insights. Genomic selection using large data requires a lot of computing power, particularly when large fractions of the population are genotyped. Theoretical improvements have made possible the inversion of large numerator relationship matrices, permitted the solving of large systems of equations, and produced fast algorithms for variance components estimation. Recent work shows that single-step approaches combining BLUP with a genomic relationship (G) matrix have similar computational requirements to traditional BLUP, and the limiting factor is the construction and inversion of G for many genotypes. A naive algorithm for creating G for 14,000 individuals required almost 24 h to run, but custom libraries and parallel computing reduced that to 15 m. Large datasets also create challenges for the delivery of genetic evaluations that must be overcome in a way that does not disrupt the transition from conventional to genomic evaluations. Processing time is important, especially as real-time systems for on-farm decisions are developed. The ultimate value of these systems is to decrease time-to-results in research, increase accuracy in genomic evaluations and accelerate rates of genetic improvement.

Improving survival is a continuous objective in swine breeding. The aim of this study was to record 22 blood parameters and weight gain the first day of life in Landrace-Yorkshire-Duroc crossbred piglets and to find associations between these parameters and survival at weaning. All live piglets from 18 litters were weighed and blood sampled at birth and d 1 and monitored to weaning at the age of 5 wk. A total of 261 piglets were born, of which 8.8% were stillborn. Additionally, 15.1% died before weaning. The blood parameters glucose, immunoglobulins, and white blood cells increased from birth to d 1 (P < 0.001), whereas α₁- and β₁ globulin, red blood cells, hemoglobin, and hematocrit decreased (P < 0.001). At birth, levels of lactate (P = 0.004), pH (P = 0.007), red blood cells (P = 0.017), hemoglobin (P = 0.018), and hematocrit (P = 0.052) were associated with survival to weaning. Also, levels of lactate increased (P = 0.030), and pH decreased (P < 0.001) when born in the last third of a litter. At d 1, levels of glucose (P = 0.015), hemoglobin (P = 0.025), and weight gain (P = 0.001) were all decreased in piglets that did not survive to weaning. Weight gain also decreased (P = 0.005) when born in the last third of a litter. Level of IgG at d 1 was not associated with survival at weaning (P = 0.230), but decreased (P < 0.001) when born in the last third of a litter. We conclude that several blood parameters recorded at birth and d 1, and weight gain at d 1 were highly associated with survival at weaning, and that being born in the last third of the litter was less favorable with regard to vitality.

Residual feed intake (RFI) has been explored as an alternative selection criterion to feed conversion ratio (FCR) to capture the fraction of feed intake not explained by expected production and maintenance requirements. Selection experiments have found that low RFI in the growing pig is genetically correlated with reduced fatness and feed intake. Selection for FCR also reduces sow appetite and fatness, which, together with increased prolificacy, has been envisioned as a hindrance for sow lifetime performances. The aims of our study were to derive equations for sow RFI during lactation (SRFI) and to evaluate the impact of selection for RFI during growth on sow traits during lactation. Data were obtained on two divergent lines selected for seven generations for low (high) RFI during growth in purebred Large White. RFI was measured on candidates for selection (1065 pigs), and sow performances were available for 480 sows having from one to three parities (1071 parities). Traits measured were sow daily feed intake (SDFI), sow BW and body composition before farrowing and at weaning (28.4 ± 1.7d), number of piglets total born, born alive and surviving at weaning, and litter weight, average piglet weight and within-litter SD of piglet weights at birth, 21 d of age (when creep feeding was available) and weaning. Sow RFI was defined as the difference between observed SDFI and SDFI predicted for sow maintenance and production. Daily production requirements were quantified by litter size and daily litter weight gain, as well as daily changes in sow body reserves. SRFI represented 24% of the phenotypic variability of SDFI. Heritability estimates for RFI and SRFI were both 0.14. The genetic correlation between RFI and SRFI was 0.29 ± 0.23. Genetic correlations of RFI with sow traits were low to moderate, consistent with responses to selection: selection for low RFI during growth reduced SDFI and increased number of piglets and litter growth, but also increased mobilization of body reserves. No impact on rebreeding performances was found. Metabolic changes previously observed during growth in response to selection might explain part of the better efficiency of the low-RFI sows, lowering basal metabolism and favouring rapid allocation of resources to lactation. Finally, we propose to consider SRFI as an alternative to SDFI to select for efficient sows with lower input demands during lactation.

Neurogastroenterology is a subspecialty encompassing relations of the nervous system to the gastrointestinal tract. The central concept is emergence of whole organ behavior from coordinated activity of the musculature, mucosal epithelium and blood vasculature. Behavior of each effector is determined by the enteric nervous system (ENS). The ENS is a minibrain positioned close to the effectors it controls. ENS neurophysiology is in the framework of neurogastroenterology. The digestive tract is recognized as the largest lymphoid organ in the body with a unique compliment of mast cells. In its position at the ‘dirtiest’ of interfaces between the body and outside world, the mucosal immune system encounters food antigens, bacteria, parasites, viruses and toxins. Epithelial barriers are insufficient to exclude fully the antigenic load, thereby allowing chronic challenges to the immune system. Observations in antigen-sensitized animals document direct communication between the mucosal immune system and ENS. Communication is functional and results in adaptive responses to circumstances within the lumen that are threatening to the functional integrity of the whole animal. Communication is paracrine and incorporates specialized sensing functions of mast cells for specific antigens together with the capacity of the ENS for intelligent interpretation of the signals. Immuno-neural integration progresses sequentially beginning with immune detection followed by signal transfer to the ENS, followed by neural interpretation and then selection of a neural program with coordinated mucosal secretion and a propulsive motor event that quickly clears the threat from the intestinal lumen. Operation of the defense program evokes symptoms of cramping abdominal pain, fecal urgency, and acute watery diarrhea. Investigative approaches to immuno-ENS interactions merge the disciplines of mucosal immunology and ENS neurophysiology into the realm of neurogastroenterology.

Stem cell niche plays a critical role in regulating the behavior and function of adult stem cells that underlie tissue growth, maintenance and regeneration. In the skeletal muscle, stem cells, called satellite cells, contribute to postnatal muscle growth and hypertrophy, and thus, meat production in agricultural animals. Satellite cells are located adjacent to mature muscle fibers underneath a sheath of basal lamina. Microenvironmental signals from extracellular matrix mediated by the basal lamina and from the host myofiber both impinge on satellite cells to regulate their activity. Furthermore, several types of muscle interstitial cells, including intramuscular preadipocytes and connective tissue fibroblasts, have recently been shown to interact with satellite cells and actively regulate the growth and regeneration of postnatal skeletal muscles. From this regard, interstitial adipogenic cells are not only important for marbling and meat quality, but also represent an additional cellular component of the satellite cell niche. At the molecular level, these interstitial cells may interact with satellite cells through cell surface ligands, such as delta-like 1 homolog (Dlk1) protein whose overexpression is thought to be responsible for muscle hypertrophy in callipyge sheep. In fact, extracellular Dlk1 protein has been shown to promote the myogenic differentiation of satellite cells. Understanding the cellular and molecular mechanisms within the stem cell niche that regulate satellite cell differentiation and maintain muscle homeostasis may lead to promising approaches to optimizing muscle growth and composition, thus improving meat production and quality.

The regulation of nutrient absorptive capacity is a critical factor in the normal growth and development of infants of all species. In human infants this is a common problem following surgical resection; the process of adaptation, or up-regulation of nutrient transport capacity is the physiologic process, which allows patients to transition to enteral feeding. The specific mechanisms which control this are still relatively poorly understood but are likely relevant for most mammals with an ontogeny of intestinal function related to the weaning process. Many actions of the entero-endocrine hormone glucagon-like peptide (GLP)-2 indicate that it may be a key factor in regulating physiologic intestinal development, nutrient absorptive capacity and the process of adaptative upregulation of nutrient absorption following resection. This article will review the biology of GLP-2 which is preserved across a broad range of species. This will include the production of GLP-2 in the L cell, the regulation of GLP-2 release and the mechanism of action. The GLP-2 receptor is specifically located on enteric neurons, and pericryptal myofibroblast; thus, effects on the intestinal mucosa involve a second messenger. We will review the functioning of this system in the developing human infant and the role of GLP-2 in the regulation of adaptation, with the general implications for nutrient absorption in animals and humans.

Feed intake has been shown to alter neurological signaling related to feeding behavior and subsequent activation of adipogenic mechanisms. Fat characteristics are pivotal for carcass and meat quality, including marbling score, flavor, and tenderness. The objective of this study was to establish the association of SNP, from genes functionally related to fat metabolism and obesity, with growth, fat, and carcass traits in steers. A total of 33 informative SNP from candidate genes [cocaine- and amphetamine-regulated transcript (CART), DNA-protein kinase (DNA-PK), fatty acid synthase (FASN), and fat mass and obesity associated (FTO)] were used to genotype crossbred steers (n=620), and associations with growth and carcass traits were assessed. Five markers within the DNA-PK gene were associated (P < 0.05) with fat thickness. One of these SNP was also associated (P < 0.05) with percent choice, yield grade, and retail product yield. Additionally, two unique DNA-PK SNP were associated (P < 0.05) with marbling score. Three haplotypes were observed using these SNP and were significantly (P = 0.0014) associated with marbling score. Harvest weight, average daily gain, and hot carcass weight were associated (P < 0.05) with SNP from CART, FTO, and FASN. Data from this study indicate that polymorphisms within candidate genes have an indirect relationship with lipogenesis. Replication of these results within other populations will be necessary to establish if these markers will be successful as predictors of fatness components and carcass traits in cattle.

A study was conducted to evaluate feed intake, ADG, carcass quality, eating behavior and blood metabolites in feedlot beef steers fed diets that varied in proportion of wheat dried distillers grains with solubles (DDGS) replacing barley grain or barley silage. Two hundred crossbred steers (BW = 489 ± 30 kg) were blocked by weight and randomly allotted to 20 pens (5 pens per treatment). Steers were fed one of four diets: control without DDGS (CON), 25% (25DDGS), 30% (30DDGS), or 35% (35DDGS) wheat DDGS (DM basis). The CON diet consisted of 15% barley silage and 85% barley-based concentrate; the three wheat DDGS diets were formulated by substituting 20% barley grain and 5, 10 or 15% silage, respectively, with 25, 30 or 35% wheat DDGS so that the 35DDGS diet contained no silage. The diets were formulated such that wheat DDGS was substituted for both barley grain and barley silage to evaluate whether wheat DDGS can be fed as a source of both energy and fiber in feedlot finishing diets. Dry matter intake of steers fed 25DDGS was greater (P < 0.01), but final BW, ADG and G:F were not different compared to steers fed CON diet. Carcass characteristics and liver abscess score were not different between CON and 25DDGS. Steers fed 25DDGS had longer eating time (min/d; P < 0.01), greater meal frequency (P < 0.04), but a slower eating rate (P < 0.04). Replacing barley silage with increasing levels of wheat DDGS (from 25DDGS to 35DDGS) linearly reduced (P < 0.01) DMI. Final BW, ADG and G:F were not affected by increasing levels of wheat DDGS. Carcass traits were not different whereas liver abscess scores linearly (P < 0.01) increased as more barley silage was replaced by wheat DDGS. Eating time (min/d) and duration of each meal linearly (P < 0.02) decreased, whereas eating rate (min/g DM) linearly (P < 0.01) increased with increasing replacement of barley silage. Blood urea N was doubled (P < 0.01) compared with CON by inclusion of wheat DDGS. Results indicate that wheat DDGS can be used effectively in feedlot diets, decreasing the need for barley grain or silage without negatively affecting growth performance and carcass characteristics. A reduction in the level of roughage required to maintain growth performance is a potential advantage in feedlot operations as forage is costly and often of limited availability. Thus, DDGS can be a possible alternative as long as they are available and cost-effective; however, increased incidence of liver abscess and high N content of manure need to be considered when high levels of wheat DDGS are included in finishing diets.

Mammary development proceeds from an aggregation of cells in the ventral ectoderm to the establishment of an elaborate tree of alveoli, ducts, and cisternae. However, despite abundant data on endocrine regulation of ruminant mammary growth, we know comparatively little about cell lineages, expression of differentiation markers, and plasticity in mammary cell phenotype. Histologic analyses have revealed cell populations with distinct histochemical profiles, but functional assessment of the cell populations during development has been limited to analysis of proliferation and frequency estimations of morphotypes. The lack of transplantation models, limited availability of validated antibodies with reactivity to bovine antigens, and similar technical challenges have generally hindered the pace of discovery, but the application of new technologies such as laser microdissection, transcriptional profiling, and multispectral image analysis are yielding important clues into bovine mammary cell ontogeny and developmental regulation. Our analyses have shown that prepubertal ovariectomy affects epithelial architecture, increases the proportion of cells expressing the estrogen receptor, and increases myoepithelial cell development, all concomitant with dramatic reduction in the mass of parenchymal tissue. Our observations point to a dual role for ovarian secretions in the control of not only the rate of epithelial development, but also the nature of the parenchymal development. The balance of stimulus and inhibition pathways cooperatively regulates mammary growth. The increased reliance on objective staining analyses and quantitative approaches will ensure broader repeatability, application, and extension of the findings regarding the impact of the ovary and other regulatory entities and factors. Advances in understanding the ontogeny of mammary epithelial cells, coupled with the established and increasing knowledge of endocrine factors affecting mammary development may yield intervention strategies to improve dairy profitability.

An experiment was conducted to determine the influence of adding graded levels of microbial phytase to corn, distillers dried grains with solubles (DDGS), high protein distillers dried grains (HP-DDG), and corn germ on the standardized total tract digestibility (STTD) of P. A second objective was to develop regression equations to predict the response of adding phytase to each of these ingredients. Four corn-based diets, 4 DDGS-based diets, 4 HP-DDG-based diets, and 4 corn germ-based diets were formulated. The 4 diets with each ingredient were formulated to contain 0, 500, 1,000, or 1,500 phytase units (FTU)/kg. A P-free diet was also formulated to determine basal endogenous losses of P. A total of 102 pigs (initial BW: 18.2 ± 2.1 kg) were individually housed in metabolism cages equipped with a feeder, a nipple drinker, and a screen floor that allowed for total collection of feces. Pigs were allotted to the 17 diets in a randomized complete block design with 6 replicate pigs per diet. Pigs were fed their respective diets for 12 d and feces were collected quantitatively from d 6 to 11. Supplementation with 500, 1,000, or 1,500 FTU of microbial phytase/kg increased (linear, P <0.01; quadratic, P < 0.05) the STTD of P in corn from 40.9 to 67.5, 64.5, and 74.9%, respectively, tended to increase (linear, P = 0.07) the STTD of P in DDGS from 76.9 to 82.9, 82.5, and 83.0%, respectively, increased (linear, P < 0.01; quadratic, P < 0.05) the STTD of P in HP-DDG from 77.1 to 88.0, 84.1, and 86.9%, respectively, and increased (linear and quadratic, P < 0.01) the STTD of P in corn germ from 40.7 to 59.0, 64.4, and 63.2%, respectively. Regression equations were developed to calculate the STTD of P in corn and corn germ, and R² values were 0.63 and 0.79, respectively. However, for DDGS and HP-DDG, the R² values were only 0.20 and 0.36, respectively, and these equations were, therefore, not considered adequate to predict the STTD of P. In conclusion, the increase in the STTD of P in corn and corn germ that is a result of microbial phytase can be predicted by regression equations, but microbial phytase has much less of the effect on the STTD of P in DDGS and HP-DDG and responses to addition of graded levels of P to these ingredients can, therefore, not be accurately predicted by regression equations.

This work aims to estimate the genetic parameters of seminal and production traits in a paternal line of rabbits selected for average daily gain during the fattening period (ADG). The considered traits were: male libido (Lib) defined as successful mounting to an artificial vagina; presence of urine (Ur) and calcium carbonate deposits (Ca) in the ejaculate; semen pH; individual sperm motility (IM); the suitability for AI of the ejaculate (Sui), which involves the subjective combination of several quality traits; the average ejaculate volume (Vol); sperm concentration (Conc); and the average sperm production per ejaculate (Prod=Vol x C). The genetic relationship between all of these traits with ADG is also provided. Male libido and seminal data came either from routine evaluations of the ejaculates in an AI center or from two experiments, in which bucks from the same population were used. Two consecutive ejaculates per male and per week were collected leaving 7 days within weekly collections. A linear tri-trait model was used to analyze Conc, Vol and ADG whereas linear and threshold-linear two-trait models were used to analyze male libido and the remaining seminal traits with ADG. A Bayesian approach was adopted for inference. Approximately 38% of ejaculates were rejected for AI primarily due to low IM scores. Variables related to the quality of the ejaculate (Ur, Ca, pH, IM, Sui) and Lib were found to be lowly heritable (h² ranged from 0.04 to 0.11), but repeatable. This indicates performance of bucks for seminal quality traits and libido in AI centers would be more strongly affected by management practices rather than genetic selection. Semen production traits exhibited moderate values of h² (0.22, 0.27 and 0.23 for Conc, Vol and Prod, respectively) suggesting the possibility of effective selection for these traits. A moderate to high negative genetic correlation (r_g) (posterior mean; highest posterior density at 95%, HPD_95%) was estimated between Conc and Vol (-0.53, HPD_95%=-0.76, -0.27). The ADG was estimated to have a h² of 0.16, to have a low, positive r_g with Conc (0.21, HPD_95%= -0.03, 0.48), to have a low, negative r_g with Vol (-0.19, HPD_95%=-0.47, 0.08), and to be genetically uncorrelated with all remaining traits analyzed. Therefore, selection for increasing ADG in paternal lines is expected to have no detrimental effects on Ur, Ca, pH, IM, Sui and Lib and little to no effect on Conc, Vol and Prod.

The aim of this study was to investigate the effects of long-distance road transport (19 h, from Poland to Italy) during 2 seasons (summer vs. winter) on clinical and hematological parameters in calves. The environmental temperature range that could compromise the calves’ thermoregulation system (thermal stress) was tested. For the 7 Holstein calves in each transport, the BW and rectal temperature (RT) were measured, and blood samples were collected at the farm of origin (T1), before loading at the transit center (T2), after unloading at the farm of destination (T3), and 1, 2, 3, and 4 d after arrival (T4, T5, T6, and T7, respectively). The body temperature (BT) and heart rate (HR) were continuously monitored from T2 to T3. The data were statistically analyzed according to a mixed model that considered the fixed effects of transport (repeated measurements), season of journey, and their interactions. Within the observed temperature-humidity index (THI) range (30 to 80), effective thermoregulation allowed the calves to maintain their BT with small physiologic changes to prevent thermal stress, particularly in the summer. With no seasonal differences, the HR was higher at loading than unloading (120 vs. 115 beats per min [bpm]; P = 0.012). As for the transport effect, the BW was less (P < 0.001) after unloading, and the RT was higher (P = 0.004). This effect was more marked in summer. The hematological parameters indicated a moderate effect of transport on the hydration condition, reactive and muscular systems, and metabolism, although hematocrit (HCT; P = 0.004), erythrocytes, cortisol, NEFA, β-hydroxybutyrate, lactate, creatine kinase, lactate dehydrogenase, and aspartate aminotransferase activity (P < 0.001), and total protein (TP; P = 0.007) were greater after unloading. This was confirmed by a moderate decrease in total leukocytes (P = 0.031) and glucose concentration (P = 0.002). The changes in the clinical parameters were similar for both seasons even though in the summer, HCT (P < 0.001), urea (P = 0.008), and TP (P = 0.010) increased and glucose concentration (P = 0.038) decreased. In conclusion, the data did not show a pronounced effect due to the season of the journey. Long-distance road transport leads to notable changes in the clinical and hematological parameters at the end of the journey. However, these parameters remained within their physiological ranges and returned to basal values within a few days after the journey.

Genetic and phenotypic parameters were estimated for production and disease traits (including dagginess) from about two million pedigree recorded animals born between 1990 and 2008 in New Zealand dual-purpose ram breeding flocks. This is the most comprehensive study of genetic parameter estimates for the New Zealand sheep industry to date and includes estimates that have not previously been reported. Estimates of heritability were moderate for live weight at 8 months (LW8), fleece weight at 12 months (FW12), dag score at 3 and 8 months (DAG3, DAG8) (0.31 to 0.37), typical for weaning weight (WWT), faecal egg count in summer (FEC1) and autumn (FEC2), and analogously nematodirus counts (NEM1, NEM2) (0.17 to 0.21) and low for number of lambs born in ewes (NLB) (0.09). The genetic correlations among production traits, WWT, LW8, and FW12, were positive and moderate to high. Correlations of DAG3 and DAG8 with production and disease traits were low and mostly negative. NLB had low, but typically positive, correlations with other traits. Disease traits also had low, but positive correlations with production traits (WWT, LW8, and FW12), and were highly correlated among themselves. In general the heritability estimate for live weights and dagginess were higher than what is currently used in the New Zealand genetic evaluation service (Sheep Improvement Limited) and the availability of accurate estimates for dagginess plus parasite resistance and their genetic correlations with production traits will enable more accurate breeding values (BVs) to be estimated for New Zealand sheep.

It has long been appreciated that animals fed the same diet may perform differently. This is due to the ability of nutrients to interact with and affect molecular pathways that result in differences in weight gain, production performance or disease resistance. To understand these effects, studies are being undertaken to discover how the differential expression and function of genes occurs with different diets. These studies are utilizing new technologies, genomic resources and analysis techniques that have recently become available for domestic animals. Nutrigenomics and nutrigenetics are new research approaches that strive to optimize health by looking beyond the diet to understand the effects of food at the genetic and epigenetic levels. Nutrigenomics is focused on the effects of diet on health through an understanding of how bioactive chemicals in foods and supplements alter gene expression or the structure of an animal’s genome. Nutrigenetics focuses on the how the genetic composition (i.e., genetic variation) of an animal influences their response to a given diet. Results from these studies will aid in formulating nutritionally appropriate diets that may be optimized for animals based on their genomic underpinnings. Nutrigenomics and nutrigenetics unite many fields: nutrition, bioinformatics, molecular biology, genomics, functional genomics, epidemiology and epigenomics. The use of multi-disciplinary tools promises new opportunities to investigate the complex interactions of the genome and an animal’s diet. Through these new approaches, the partnerships of the genome and nutrition will be revealed resulting in improved efficiency of diets, enhanced sustainability of animals as a protein source and improved methods for preventing illnesses.

We predicted that zilpaterol hydrochloride (ZH), β-adrenergic receptor (AR) agonist would depress mRNA and protein level of ß-ARs in bovine satellite cells. We also predicted that ZH would decrease total lipid synthesis in bovine adipose tissue. Bovine satellite cells isolated from the semimembranosus muscle were plated on tissue culture plates coated with reduced growth factor matrigel or collagen. Real-time quantitative-PCR was used to measure specific gene expression following 48 h of ZH exposure in proliferating satellite cells and fused myoblasts. There was no effect of ZH dose on [³H]-thymidine incorporation into DNA in proliferating myoblasts. Zilpaterol hydrochloride at 1 µM decreased (P < 0.05) β1-AR mRNA and 0.01 and 1µM ZH decreased (P < 0.05) β2-AR and β3-AR mRNA in myoblasts. The expression of IGF-I mRNA tended to increase (P = 0.07) with 1 µM ZH. There was no effect (P > 0.05) of ZH on the expression ß-AR or IGF-I gene expression in fused myotube cultures at 192 h, or on fusion percentage. The β2-AR antagonist ICI-118, 551 at 0.1 µM attenuated the effect of 0.1 µM ZH to reduce expression of β1 and β2-AR mRNA. The combination of 0.01 µM ZH and 0.1 µM ICI-118, 551 caused an increase (P < 0.05) in β1-AR gene expression. There was no effect of ICI-118, 551 or ZH on β3-AR or IGF-I. Western blot analysis revealed that the protein content of β2-AR in ZH-treated myotube cultures decreased (P < 0.05) relative to control. Total lipid synthesis from acetate was increased by ZH in bovine s.c. adipose tissue explants in the absence of theophylline, but was decreased by ZH when theophylline was included in the incubation medium. These data indicate that ZH alters mRNA and protein concentrations of β-AR in satellite cell cultures, which in turn could impact responsiveness of cells to prolonged ZH exposure in vivo. Similar to other ß-adrenergic agonists, ZH had only modest effects on lipid metabolism in adipose tissue explants.

Genetic selection for increased milk production in dairy cattle was not associated with an attenuated inflammatory response. The systemic and local inflammatory responses contribute to altered metabolism, reduced production performance, and high cull rate of lactating dairy cows with clinical mastitis. More aggressive inflammatory responses were observed during the peripartum period when compared with cows in late lactation following an intra-mammary challenge with purified lipopolysaccharide. The epidemiology of clinical mastitis indicates the greatest incidence is observed during the peripartum period; therefore, an enhanced inflammatory response with concomitant suppression in other immune responses may be involved in the etiology and severity of the clinical mastitis observed in peripartum cows. Milk production losses and compositional changes are observed among all mammary quarters from a cow with clinical mastitis, but the responses are more severe and sustained among infected quarters. The infected mammary quarters reflect both the systemic and local reactions; whereas uninfected quarters only represent the systemic response. The systemic effects of the inflammatory response include: reduced dry matter intake, hyperthermia, and changes in whole-body nutrient partitioning affecting mammary epithelial substrate availability; whereas local inflammatory effects include energetic requirements of the increased inflammatory leukocyte pool, decreased synthetic capacity of mammary epithelium independent of substrate availability, and paracellular leakage of milk components from the alveolar lumen into the extracellular fluid. Research has focused on improving host immunological defenses, attenuating the inflammatory response, or improving the resolution of the disease state to limit the deleterious effects during clinical mastitis. This paper will highlight role inflammation plays in the etiology and pathophysiology of clinical mastitis as well as potential management strategies to reduce or prevent those losses.

The present study investigated the effect of 3 different durations of feeding a diet supplemented with defatted bovine colostrum (Col) on growth performance and sanitary status of the weaned piglet. At 28 d of age, piglets were weaned and fed 1 of the 2 following diets: a control (Ctrl) starter diet or a starter diet supplemented with Col. Two experiments were conducted. In Exp. 1, 310 piglets (12 pens consisting 10 piglets/pen and 10 pens consisting 19 piglets/pen) were allocated to 1 of the 2 dietary treatments for 12 d. In Exp. 2, 522 piglets (18 pens consisting 10 piglets/pen and 18 pens consisting 19 piglets/pen) were allocated to 1 of the following 3 dietary treatments: fed the Ctrl diet from d 1 to 12 (Ctrl), Col diet from d 1 to 4 and then the Ctrl diet up to d 12 (Col-4d), or the Col diet from d 1 to 6 and then the Ctrl diet up to d 12 (Col-6d). For both experiments, a commercial second phase diet was fed to piglets from d 12 to 46. Feed intake, growth performance, and cleanliness of floor and hindquarters of animals were investigated during the first 7 post-weaning wk. In Exp. 1, from d 0 to 12, ADFI, ADG, and G:F were 16 (P = 0.004), 23 (P < 0.001), and 5% (P = 0.069) greater, respectively, in Col piglets compared to Ctrl piglets. Thereafter, ADFI and ADG were 7 (P < 0.001) and 9% (P < 0.001) greater, respectively, in Col piglets than Ctrl piglets (d 12 to 46). On d 12 after weaning, piglets fed the Col diet had more normal feces (+13%) and less soft or liquid feces (-9 and -4%, respectively) than piglets fed the Ctrl diet (P = 0.06). Compared to Ctrl piglets, feeding the Col diet led to more days with normal feces for the floor cleanliness (+22%; P < 0.001) from d 7 to 11. In Exp. 2, compared with Ctrl piglets, ADFI, ADG, and G:F were 8, 23, and 13% greater (P < 0.05) in Col-6d piglets from d 0 to 9, whereas values for Col-4d piglets were intermediate and did not differ from the values of the other dietary treatments. On d 9 after weaning, piglets fed the Col-4d or the Col-6d diet had more normal feces (+6 and +4%, respectively) and less liquid feces (-4 and -3%, respectively) than piglets fed the Ctrl diet (P = 0.08). No long lasting effects were observed thereafter. In conclusion, there was a reduction of weaning-induced growth check and diarrheal episodes in weaned piglets fed the Col diet. The beneficial effects of the bovine colostrum were observed beyond the period of treatment when the supplementation covered the first 6 d post-weaning, which corresponded to the acute phase of postweaning digestive disturbances.

Dietary CLA has been reported to decrease backfat and increase marbling in pigs. Our objective was to determine if the increase in marbling involved changes in intramuscular adipocyte number or size, or both. Twenty barrows (53 kg) were penned in pairs and pens were randomly assigned to receive diets containing either 1% soybean oil (SBO) or CLA (60% CLA isomers) for 6 wk. Body weight and feed intake were determined weekly. At slaughter, loin samples were obtained and flash frozen for RNA extraction and real time reverse transcription-PCR analysis of gene expression. Following a 24-hr chill, loin eye area (LEA) and backfat depth (BF) were measured, and subjective marbling and color scores were assigned. Loin, backfat, and belly fat samples were obtained for fatty acid analysis by gas chromatography. Loin samples were also frozen in ice-cold isopentane for histological analysis of intramuscular adipocytes. Dietary CLA did not affect BW or feed intake at any point (P > 0.05), nor did treatment groups differ in HCW (P = 0.417) or loin color (P = 0.500). The CLA-fed pigs did have less (P = 0.018) backfat and smaller (P = 0.047) LEA than SBO-fed pigs and had a trend for an increase (P = 0.069) in marbling score. Relative gene expression for markers of preadipocytes (Pref-1), differentiating adipocytes (PPAR), and mature adipocytes (FABP4 and PLIN) were determined and normalized to the expression of acidic ribosomal phosphoprotein (ARP). No significant differences were detected, but the expression of PPAR (P = 0.265), PLIN (P = 0.265), and FABP4 (P = 0.148) all were numerically greater in CLA-fed pigs than SBO-fed pigs. Loin samples were stained with Oil Red O to identify intramuscular adipocytes. The average cell area was increased (P = 0.030) in CLA-fed pigs. The cis9,trans11 and trans10,cis12 CLA isomers were incorporated (P = 0.006) into backfat and belly fat but only trans10,cis12 CLA was increased in the loin (P = 0.004) of CLA-fed pigs. The proportion of saturated fatty acids was increased (P = 0.006) by CLA in all tissues. These results indicate that the increase in marbling in pigs fed CLA may be related to increased intramuscular adipocyte size, and the combination of increased marbling and degree of saturation could improve the eating quality of CLA-fed pork.

This paper compares energy use for different pig production systems in Iowa, a leader in U.S. swine production. Pig production systems include not only the growth and performance of the pigs but also the supporting infrastructure of pig production. This supporting infrastructure includes swine housing, facility management, feedstuff provision, swine diets, and manure management. Six different facility type x diet formulation x cropping sequence scenarios were modeled and compared. The baseline system examined produces 15,600 pigs annually using confinement facilities and a corn-soybean cropping sequence. Diet formulations for the baseline system were corn-SBM diets that include synthetic amino acid L-Lysine and exogenous phytase. The baseline system represents the majority of current U.S. pork production in the Upper Midwest where most U.S. swine are produced. This system was found to require 744.6 MJ per 136-kg market pig. An alternative system that uses bedded hoop barns for grow-finish pigs and gestating sows would require 3% less (720.8 MJ) energy per 136-kg market pig. When assessing swine production systems, diet type and feed ingredient processing are the major influences on energy use, accounting for 61% and 79% of total energy in conventional and hoop barn-based systems respectively. Improving feed efficiency and better matching diet formulation with thermal environment and genetics is thus a key aspect of reducing energy use by pig production, particularly in a hoop barn-based system. The most energy-intensive aspect of provisioning pig feed is production of synthetic nitrogen for crop production, thus effectively recycling manure nutrients to cropland is another important avenue for future research. Nearly 25% of energy use by a conventional farrow-to-finish pig production system is attributable to operation of the swine buildings. Developing strategies to minimize energy use for heating and ventilation of swine buildings while maintaining pig comfort and performance is a third critical area for future research. The hoop barn-based alternative uses 64% less energy to operate buildings but requires bedding and 2.4% more feed. Current Iowa pig production systems use energy differently but result in similar total energy use. Compared to 1975, current farrow-to-finish systems in Iowa require 80% less energy to produce live market pigs.

Pure-bred embryos were transferred within and reciprocally between large (Suffolk: S) and small (Cheviot: C) breeds of sheep to establish 4 treatment groups; SinS (Suffolk embryos in Suffolk dams), SinC (Suffolk embryos in Cheviot dams), CinS (Cheviot embryos in Suffolk dams) and CinC (Cheviot embryos in Cheviot dams). The recipient ewes carried single fetuses to term. The maternal plasma concentrations of ovine placental lactogen (oPL), progesterone, IGF-1, FFA and glucose were measured on d 50, 90, 120 and 140 of pregnancy. Birth weight, body dimensions and placental characteristics of lambs were recorded at birth. There was a recipient ewe breed x lamb breed x time interaction for the concentration of oPL (P = 0.03), but no such interaction was observed for progesterone (P = 0.42), IGF-1 (P = 0.57), glucose (P = 0.36) and FFA (P = 0.72). There were no differences in oPL (P = 0.28) and progesterone (P = 0.34) concentrations between SinC and SinS ewes. The concentrations of FFA on d 140 (P = 0.008), and those of glucose on d 50 (P = 0.02), and 120 (P = 0.01), were greater in SinC ewes than in SinS ewes. The ewes in CinS had lower FFA concentration (P = 0.002) at all time points than CinC ewes. The concentrations of IGF-1 on d 90 were greater (P = 0.004) in CinS ewes than CinC ewes, but did not differ (P = 0.16) on d 50, 120 and 140. The concentrations of glucose on d 50 (P = 0.001), 90 (P = 0.03) and 140 (P = 0.03) were lower in CinS ewes compared with CinC ewes. The birth weight of SinC lambs (5.04 ± 0.20 kg) was lower (P = 0.001) than SinS lambs (5.94 ± 0.19 kg) and body dimensions of SinC lambs were smaller (P = 0.01) than SinS lambs. Neither birth weight nor the body dimensions of CinS lambs differed (P = 0.24) from CinC lambs. Cotyledon number was lower (P = 0.04) in CinS (57.5 ± 6.3) than SinS group (74.2 ± 5.9), whereas, mean cotyledon weight in CinS (2.42 ± 0.20 g) was greater (P = 0.02) than SinS (1.74 ± 0.21 g). It was concluded that the large genotype lambs were lighter and smaller when born to small genotype dams; however, the birth weight or body dimensions of small genotype lambs did not differ when born to large genotype dams. This study suggests that plasma oPL, progesterone, IGF-1, FFA and glucose concentrations at different times throughout pregnancy reflect the regulatory effect of the uterine environment on the development of the fetus.

To test the effect of insulin on renal perfusion and the participation of nitric oxide and prostaglandins as mediators of this response, renal blood flow (RBF) was measured in sheep (n = 8) implanted with ultrasonic flowprobes around renal arteries and with a systemic arterial pressure (SAP, n = 4) telemetry device. Three protocols were performed: 1) RBF and SAP recorded (0800 to 1800 h) in fed and fasted sheep where the latter received i.v. infusions (0.5 mL/min) of insulin at 2 or 6 mU/(kg•min); 2) fasted sheep received i.v. infusions of either an inhibitor of the nitric oxide synthesis (N^G-nitro-L-arginine methyl ester, L-NAME) alone [0.22 mg/(kg•min), 1000 to 1200 h] or L-NAME (1000 to 1200 h) + insulin during the second hour (6 mU/(kg•min), 1100 to 1200 h); and 3) the same protocol as in protocol 2, substituting L-NAME with ketoprofen [0.2 mg/(kg•min)], a cyclooxygenase inhibitor. In all protocols, plasma insulin and glucose were determined. During insulin administration, euglycemia was maintained and hypokalemia prevented by infusing glucose and KCl solutions. After the onset of meals, a long-lasting 18% rise in RBF and a 48% insulin increase were observed (P < 0.05), without changes in SAP. Low- and high-dose insulin infusions increased RBF by 19 and 40%, respectively (P < 0.05). As after meals, the rises in RBF lasted longer than the insulin increase (P < 0.05). The L-NAME infusion decreased RBF by 15% (P < 0.05); when insulin was added, RBF rose to pre-infusion values. Ketoprofen decreased RBF by 9% (P < 0.05); when insulin was added, RBF rose to 13% above pre-infusion values (P < 0.05). In no case were SAP or glucose modifications noted during the RBF changes. In conclusion, insulin infusion mimics the meal-dependent rise in RBF, independent of SAP, and lasts longer than the blood insulin plateau. The RBF increase induced by insulin was only partially prevented by L-NAME. Ketoprofen failed to prevent the insulin-dependent RBF increase. Both facts suggested that complementary vasodilatatory agents accounted for the insulin effect on sheep renal hemodynamics.

Sperm quality is often evaluated through computer-assisted semen analysis (CASA) and is an indicator of boar fertility. The aim of this research was to study the relationship between CASA motility parameters and the fertility results in pigs. Insemination records and semen parameters from a total of 45,532 ejaculates collected over a 3-yr period were used. The statistical model for analysis of fertility data from these inseminations included factors related to sow productivity. The boar and semen-related variance (direct boar effect) were corrected for effects of individual boar, genetic line of the boar, age of the boar, days between ejaculations, number of sperm cells in an ejaculate, number of sperm cells in an insemination dose, and AI station. The remaining variance was analyzed if semen motility parameters had a significant effect. This analysis revealed significant (P < 0.05) effects of progressive motility, velocity curvilinear, and beat cross frequency on farrowing rate (FR). Total motility, velocity average path, velocity straight line, and amplitude of lateral head displacement affected (P < 0.05) total number of piglets born (TNB). Boar and semen-related parameters explained 5.3% of the variation in FR and 5.9% of the variation in TNB. Motility parameters, measured by CASA, explained 9% of the boar and semen-related variation in FR and 10% of the boar and semen-related variation in TNB. Individual boar and genetic line of the boar affected (P < 0.0001) the variation in FR and TNB. There were no differences (P > 0.05) between effects of AI stations on fertility outcome, underscoring the objectivity of the CASA system used. Measuring motility parameters with CASA can be used to assess sperm motility in an objective manner. Based on the motility pattern, CASA enables one to discriminate between the fertilizing capacity of ejaculates, although this depends upon the genetic line of the boar used in AI stations.

In nonruminant herbivores, microbially-derived AA could contribute to whole body AA homeostasis and, thus, decrease predicted AA requirements; however, post-ileal capacity of AA uptake is currently unknown. Therefore, to test the hypothesis that Lys is transported across the large colon mucosal apical membrane with similar capacity to that of the small intestinal mucosa in the pony and pig, we examined Lys transport in vitro using brush border membrane vesicles (BBMV). Mucosa was collected from the distal jejunum (DJ) and proximal large colon (PLC) of growing pigs (n = 3) and ponies (n = 4), flash-frozen in liquid nitrogen, and stored at -80°C. Jejunal and colonic BBMV were manufactured by Mg²⁺ precipitation and used to determine initial rates and kinetics (V_max and K_M) of l-Lys transport into apical epithelia by rapid filtration technique in Na⁺-gradient incubation buffer. Initial rates of total l-Lys uptake did not differ between PLC and DJ in either the pig or pony, or between the pony and pig, at each individual l-Lys concentration. In the pig, compared to DJ, l-Lys transport V_max in PLC did not differ (121 ± 26 and 180 ± 26 mol·mg protein^-1·s^-1, respectively; P = 0.14) and l-Lys K_M in PLC tended to be greater (0.23 ± 0.22 vs. 0.89 ± 0.22 mM; P = 0.09). In the pony, compared to DJ, l-Lys transport V_max in PLC was greater (62 ± 25 and 149 ± 25 mol·mg protein^-1·s^-1, respectively; P = 0.04) and l-Lys K_M in PLC was greater (0.08 ± 0.22 and 1.05 ± 0.22 mM, respectively; P = 0.02). L-Lysine diffusion was not different between segments; however, total intestinal diffusion was greater (P = 0.03) in pony compared to pig (115 ± 10 and 73 ± 10 mol·mg protein^-1·s^-1, respectively). These results demonstrated that the large colon is capable of l-Lys transport across the apical epithelial membrane with higher capacity and lower affinity than the jejunum, indicating that the large colon may play a significant role in l-Lys absorption and homeostasis in hind-gut fermenters.

The present experiment was conducted to provide a validation of a previously developed model for on-line classification of U.S. Select carcasses for LM tenderness based on visible and near-infrared (VISNIR) spectroscopy and to determine if the accuracy of VISNIR-based tenderness classification could be enhanced by making measurements after postmortem aging. Spectroscopy was conducted on-line, during carcass grading, at a large-scale commercial fed-beef processing facility and the strip loin was obtained from the left side of U.S. Select carcasses (n = 467). Slice shear force (SSF) was measured on fresh steaks at 2 and 14 d postmortem. On-line VISNIR tenderness classes differed in mean SSF values at both 2 (29.4 vs 33.6 kg) and 14 (18.0 vs 21.2 kg) d postmortem (P < 10^-7). On-line VISNIR tenderness classes differed in both the percentage of carcasses with LM SSF values greater than 40 kg at 2 d postmortem (5.1 vs 21.0%; P < 10^-6) and the percentage of carcasses with LM SSF values greater than 25 kg at 14 d postmortem (6.8 vs 23.2%; P < 10^-5). Whereas 15.0% of the carcasses sampled for this experiment had LM SSF values greater than 25 kg at 14 d postmortem, only 6.8% of the carcasses classified as tender by VISNIR had LM SSF values greater than 25 kg. All of the carcasses sampled that had LM SSF values greater than 35 kg at 14 d postmortem were accurately classified as tough by VISNIR. Prior to measurement of SSF on d 14, VISNIR spectroscopy was conducted on the SSF steak. Tenderness classes based on d 14 VISNIR spectra differed both in mean SSF value at 14 d postmortem (17.7 vs 21.6 kg; P < 10^-11) and the percentage of carcasses with LM SSF values greater than 25 kg at 14 d postmortem (7.3 vs 22.7%; P < 10^-5). This data supports our previous work showing that VISNIR spectroscopy can be used to non-invasively classify U.S. Select carcasses for LM tenderness and establishes that this technology could also be applied to aged U.S. Select strip loins. This technology would allow packing companies and other segments of the beef marketing chain to identify U.S. Select carcasses or strip loins that excel in LM tenderness for use in branded beef programs.

Tall fescue (Lolium arundinaceum) toxicosis research is often complicated by a reduction in intake of infected forage or seed making treatment comparisons difficult. This study was conducted to develop a fescue toxicosis model that would allow for variations in DM intake without altering the quantity of alkaloids consumed over the course of the experiment. Ground tall fescue seed and a tall fescue seed extract were used in two, two-period crossover experiments to determine the effectiveness of ruminal dosing of a tall fescue seed extract to induce fescue toxicosis. This experiment utilized four growing Holstein steers (BW = 337 ± 24 kg) surgically fitted with ruminal cannulas. Steers were maintained on a diet of endophyte free fescue hay fed ad libitum throughout the experiment. Endophyte infected (E+; 4.1 mg/kg ergovaline) and uninfected (E-; 0.0 mg/kg ergovaline) KY-31 tall fescue seed was ground and dosed or extracted with ethanol, concentrated and lyophilized prior to ruminal dosing. Ergovaline concentration of the final extract was 102 mg/kg. Animals were given a minimum of a three week washout period between treatments. Physiological indicators were measured over 7d at 22°C (d1-3) and 32°C (d4-7) during both seed and extract dosing. Seed and extract E+ dosing reduced serum prolactin concentrations such that they were not different from zero (P < 0.10). Treatment with E+ reduced feed intake (P < 0.05) and heart rate (P < 0.001), and increased respiration rate (P < 0.01) and core temperature (P < 0.05) during both seed and extract dosing. Increasing environmental temperature from 22°C to 32°C reduced total intake (P < 0.05) and increased core temperature (P < 0.001) and respiration rate (P < 0.001) during both seed and extract dosing. Diastolic blood pressure tended (P < 0.09) to be elevated during E+ extract dosing and reduced during heat stress. These physiological alterations are consistent with those reported for cattle grazing or consuming seed from endophyte infected tall fescue. These data indicate that a ruminally dosed ethanol extract of tall fescue seed is efficacious in inducing fescue toxicosis in cattle.

The present experiments were conducted to field test a system optimized for on-line prediction of beef LM tenderness based on visible and near-infrared (VISNIR) spectroscopy and to develop and validate a model for prediction of tenderness that would be unbiased by normal variation in bloom time before application of VISNIR. For both Exp. 1 and 2, slice shear force (SSF) was measured on fresh (never frozen) steaks at 14 d postmortem. Carcasses with VISNIR-predicted SSF ≤ 15 kg were classified as VISNIR predicted tender and carcasses with VISNIR-predicted SSF > 15 kg were classified as VISNIR not predicted tender. In Exp. 1, spectroscopy was conducted on-line, during carcass grading, at three large-scale commercial fed-beef processing facilities with each carcass (n = 1,155) evaluated immediately after ribbing and again when the carcass was graded. For model development and validation, carcasses were blocked by plant and observed SSF and one-half of the carcasses (n = 579) were assigned to a calibration data set, which was used to develop regression equations, and one-half of the carcasses (n = 576) were assigned to a prediction data set, which was used to validate the regression equations. VISNIR predicted tender carcasses had lower (P < 10^-19) mean LM SSF values at 14 d postmortem in the calibration (13.9 vs 16.5 kg) and prediction data sets (13.8 vs 16.4 kg) than did VISNIR not predicted tender carcasses. Relative to carcasses not predicted tender by VISNIR, a lower percentage of carcasses predicted tender by VISNIR had LM SSF > 25 kg in the calibration (2.0 vs 7.8%) and prediction data sets (0.8 vs 8.0%). In Exp. 2, carcasses (n = 4,204) were evaluated with VISNIR on-line at six commercial fed-beef processing facilities on 38 production d. VISNIR predicted tender carcasses had lower mean LM SSF values at 14 d postmortem (16.3 vs 19.9 kg; P < 10^-87), longer sarcomere lengths (1.77 vs 1.72 µm; P < 10^-10) and a higher percentage of desmin degraded (42 vs 34%; P < 10^-5) by 14 d postmortem. Relative to carcasses not predicted tender by VISNIR, a lower percentage of carcasses predicted tender by VISNIR had LM SSF > 25 kg (4.9 vs 21.3%). The present experiments resulted in development and independent validation of a robust method to noninvasively predict LM tenderness of grain-fed beef carcasses. This technology could facilitate tenderness-based beef merchandising systems.

The objective was to review the effects of production stressors on reproductive performance of dairy cows. It has been well documented that genetic selection for milk yield over the last 50 yr has been associated with reduced fertility. In addition to negative associations between yield and conception rate, there is also an association between milk production and expression of behavioral estrus. Stress caused by production diseases in high yielding dairy cows also contributes to the problems of poor fertility. Lameness results in reduced intensity of estrus, and can contribute to ovulation failure, which is largely due to reduced pre-ovulatory estradiol secretion and failure of the LH surge. Mastitis has been associated with prolonged intervals to dominant follicle selection, and in animals with uterine infection the dominant follicle grows slower and produces less estradiol. In a recent study we identified that milk yield was associated with an increased incidence of uterine infection, which is known to contribute to reduced fertility and prolonged calving to conception intervals. The incidence of uterine disease was 73% in high-yielding, compared with 45% in low-yielding cows. As well as effects at the ovary, various models of stress have also been shown to perturb endocrine secretion in the hypothalamus and anterior pituitary. In conclusion, the adverse effects on fertility associated with genetic selection for yield in dairy cows is in part associated with increased incidences of production disease induced stress but is also associated with high milk yield.

Lysozyme is a 1,4-β-N-acetylmuramidase that has antimicrobial properties. The objective of this experiment was to determine the effect of a purified granulated lysozyme, compared to antibiotics, on growth performance, small intestinal morphology, and Campylobacter shedding in 10-d-old pigs. Forty-eight pigs (n = 16), with an initial weight of 4.0 ± 0.1 kg (P > 0.40) were weaned at 10 d of age, blocked by litter and gender, and assigned to pens (8 pigs/pen). Each block was randomly assigned to consume 1 of 3 liquid dietary treatments for 14 d; control, control + lysozyme (100 mg/kg diet), or control + antibiotics (neomycin and oxytetracycline, 16 mg/kg diet). Pigs were weighed and bled on d 0, 7, and 14. Blood was analyzed for plasma urea nitrogen (PUN) and IgA. After 14 d of treatment, pigs were killed and samples of jejunum and ileum were collected and fixed to measure villus height and crypt depth. Rectal swabs were taken on d 0, 7, and 14 of treatment, and samples of ileal and cecal contents were taken at d 14 of treatment to determine the presence of Campylobacter. Pigs consuming lysozyme and antibiotics gained at a faster rate than control pigs over the course of the study (402 ± 12 and 422 ± 14 kg/d, respectively vs. 364 ± 14 g/d; P < 0.02), resulting in heavier ending BW (9.9 ± 0.3, 9.9 ± 0.3, and 9.0 ± 0.2 kg for lysozyme, antibiotic, and control pigs, respectively; P < 0.03). Immunoglobulin A decreased and PUN increased over the course of the study (P < 0.1), regardless of dietary treatment (P > 0.6). Crypt depth was increased in lysozyme and antibiotic-fed pigs, compared to control pigs, in both jejunum (60.0 ± 2.8 and 62.2 ± 3.0, respectively vs. 50.7 ± 3.1 µm; P < 0.03) and ileum (76.0 ± 7.5 and 72.2 ± 5.0, respectively vs. 52.4 ± 3.5 µm; P < 0.02). Villus height did not differ in the jejunum (P > 0.2), but was increased in the ileum of pigs consuming lysozyme and antibiotic diets, compared to control pigs (312 ± 20 and 314 ± 10, respectively vs. 263 ± 15 µm; P < 0.4). Small intestinal total mucosa and mucosal protein concentration, as well as disaccharidase-specific activities, were not altered by lysozyme or antibiotics (P > 0.05). Campylobacter was detected in 27% of control samples, but in only 5% of antibiotic-fed samples and 8% of lysozyme-fed samples (P < 0.01). Thus, granulated lysozyme is a suitable alternative to antibiotics for 10-d-old pigs consuming manufactured liquid diets.

Newborn Ripollesa lambs (n = 143) were used to assess the optimal age at which the vascular pattern of the retina can be used as reference for identification and traceability. Retinal images from both eyes were recorded from birth to yearling (d 1, 8, 30, 82, 180 and 388 of age) in duplicate (2,534 images) using a digital camera specially designed for livestock (Optibrand, Fort Collins, CO). Intra- and inter-age image comparisons (9,316 pairs of images) were carried out and matching score (MS) used as exclusion criterion of lamb identity (MS <70). Retinal images were used for verifying the identity of live lambs of 4 Spanish commercial categories: milk-fed lambs (MF; "lechal", 1 mo of age and <12 kg BW, n = 136); light fattened lambs (LF; "recental", 3 mo of age and ~25 kg BW, n = 134); recruited replacement lambs (RR; "ovino mayor", 6 mo of age and ~35 kg BW, n = 59); and, yearling replacement lambs (YR; >12 mo of age and ~50 kg BW, n = 25). Values of MS were treated with a model based on the one-inflated bivariate beta distribution and treated data were compared by using a likelihood ratio test. Intra-age image comparisons showed that average MS and percentage of images with MS ≥70 increased with lamb age from d 1 to 82 (81.0 ± 1.0 to 95.9 ± 0.4, and 75.8 to 100%, respectively) and reached a plateau thereafter. Inter-age retinal image comparisons for MF lambs at 30 d showed that percentage of images with MS ≥70 was greater when reference images at 8-d were used instead of 1-d images (94.8 vs. 87.4%, respectively; P < 0.05). In LF lambs, 30-d retinal images matched better than those at 8 d of age (99.6 vs. 93.6%, respectively; P < 0.05). Regarding RR and YR lambs, the 82-d images allowed the confirmation of 100% lamb identity, whereas 8-d images showed a lower (P < 0.05) percentage of matching (87.9 and 89.8%, respectively for RR and YR lambs; P > 0.05); no differences were detected for 30-d images (97.4 and 98.0%, respectively for RR and YR lambs; P > 0.05). Total percentage of matching was achieved when images were obtained from older lambs (180 and 388 d). In conclusion, retinal imaging was a useful tool for verifying the identity and auditing the traceability of live lambs from suckling to yearling. Matching scores were satisfactory when the reference retinal images were obtained from 1-mo or older lambs.

The present study was conducted to characterise the in vitro antimicrobial activities of 3 essential oils [oregano, rosemary, and a commercial blend of essential oils (BEO)] against pathogenic and non pathogenic bacteria and to evaluate their effects on broiler chicken performances. The chemical composition of the essential oils was determined using the gas chromatography interfaced with a mass spectroscopy. The disc diffusion method, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) were applied for the determination of antimicrobial activities of essential oils. In vivo study, a total of 750, 1-d-old male broiler chickens were assigned to 6 dietary treatment groups: basal diet (CON), CON + 44 mg of avilamycin/kg (A), CON + 100 mg of rosemary essential oil/kg (R), CON + 100 mg of oregano essential oil/kg (O), CON + 50 mg of rosemary and 50 mg of oregano essential oils/kg (RO), and CON + 1,000 mg of BEO/kg (essential oil mixture, EOM). The essential oils isolated from rosemary and oregano were characterized by their high content in 1,8-cineole (49.99%) and carvacrol (69.55%), respectively. The BEO was mainly represented by the aldehydes (cinnamaldehyde) and the monoterpenes (1,8-cineole) chemical groups. The results of the disc diffusion method indicated that the rosemary essential oil had antibacterial activity against only 3 pathogenic bacteria including Escherichia coli (8 mm), Salmonella indiana (11 mm), and Listeria innocua (9 mm). The essential oil of oregano had antimicrobial effects on the same bacteria that rosemary plus on Staphylococcus aureus (22 mm) and Bacillus subtilis (12 mm). Oregano essential oil had greater (P ≤ 0.05) antimicrobial activities against pathogenic bacteria than rosemary essential oil but they had no synergism between them. The BEO showed a high antimicrobial activity against all studied bacteria (pathogenic and non pathogenic bacteria), except for Lactobacillus rhamnosus. The supplementation of the basal diet with avilamycin or essential oils improved (P ≤ 0.05) broiler chicken BW, BW gain, and gain to feed ratio compared with CON diet. There were no differences in growth performances among birds fed A, R, O, RO, or EOM diets. In general, essential oils contained in rosemary, oregano, and BEO can substitute growth promoter antibiotics. Although, the 3 essential oils had different antimicrobial activities, they exhibited the same efficiency in broiler chickens.

Distillers dried grains with solubles (DDGS) has low and variable AA digestibility. The variability is often attributed to damage during the heating process and it has been suggested that the damage happens to the soluble components of DDGS such as reducing sugars. Combining solubles and grains sometimes produces "syrup balls" (SB) and their digestibility is unknown. The objectives of this experiment were to identify potential sources of poor and variable AA digestibility in DDGS. Specifically, our objective was to determine whether the problems are associated with the solubles component or with SB. The ingredients evaluated were DDGS, intact SB (ISB), ground SB (GSB), liquid condensed solubles (LCS), and pulse dried thin stillage (PDTS) obtained from the same ethanol plant. The LCS is produced by evaporation of thin stillage. Each ingredient was used as the only source of AA in an experimental diet. In a duplicate 6 x 6 Latin square design with 7-d adaptation and collection periods, the 6 treatments consisted of a N-free diet and the 5 test ingredients. Pigs had 5 d of adaptation to each diet, and on d 6 and 7, ileal digesta were collected from an ileal cannula for 8 h each day. Both SB treatments had apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA that were similar or higher (P < 0.05) than those of DDGS. The AID and SID values of Lys and a few other AA were similar in LCS (SID Lys: 63.1%) and DDGS (SID Lys: 61.5%), but the digestibility values of most AA in LCS were lower than in DDGS (P < 0.05). The low digestibility of AA in LCS was most pronounced for Met (SID: LCS, 41.9% vs. DDGS, 82.8%). The LCS had lower (P < 0.05) AID and SID of CP (SID: 67.8%) than ISB (SID: 85.2%) and GSB (SID: 85.9%), as well as all AA. The PDTS generally had the lowest AID and SID, and had lower (P < 0.05) CP (SID: 55.3%) and several AA, including Lys, than LCS. In conclusion, the presence of SB does not decrease AA digestibility of DDGS, and the LCS evaluated has indispensible AA digestibility lower than DDGS. The LCS has low digestibility of AA that seems not to be caused by heat damage.

Reducing frequency of supplementation to beef cattle would reduce labor and vehicle maintenance costs and could have the potential to increase profit if performance is not negatively affected. Six ruminally cannulated beef steers (362 ± 18 kg BW) were used in a replicated 3 x 3 Latin square design to determine the effect of supplement frequency (daily or on alternate days) on digestion and ruminal parameters when feeding medium quality hay and supplementing with a mixture of soybean hulls and corn gluten feed. Dietary treatments consisted of ad-libitum fescue hay (8.8% CP and 34.8% ADF) that was supplemented at 1% BW daily (SD), supplemented 2% BW on alternate days (SA), or not supplemented (H). The supplement (14.6% CP and 29.8% ADF) contained 47% soybean hull pellets, 47% corn gluten feed pellets, 2% feed grade limestone, and 4% molasses (as-fed). Each period consisted of a 12 d adaptation phase followed by 6 d of total fecal, urine, and ort collection. All supplement offered was consumed within 2 h. Ruminal fluid was collected every 4 h for 2 d. Hay intake was reduced (P < 0.01) for SD and further reduced (P < 0.01) for SA. Hay intake was 1.54, 1.19 and 1.02% BW (SEM ± 0.036) for H, SD, and SA, respectively. There was a treatment (P < 0.01) by day interaction for mean ruminal pH. On the day of supplementation, ruminal pH for SA (6.13) was lower (P < 0.01) than both SD (6.29) and H (6.52). However, on the day SA did not receive supplement ruminal pH of SA (6.53) did not differ (P = 0.87) from H and was greater (P < 0.01) than SD. Ruminal pH of SD was lower (P < 0.01) than H. Diet DM digestibility was increased (P < 0.01) by supplementation but did not differ (P = 0.58) due to frequency. Dry matter digestibility was 57.9, 64.1, and 64.6% (SEM ± 0.65) for H, SD, and SA, respectively. The amount of N retained did not differ (P = 0.47) due to frequency (24.9 ± 5.61 and 22.0 ± 5.50 g/d for SD and SA, respectively) and was greater (P < 0.01) for the supplemented treatments than H (4.2 ± 3.30 g/d). When supplementing a blend of soybean hulls and corn gluten feed, producers can reduce frequency of supplementation to every other day without reducing digestibility or N retention.

Continuous culture and in vivo experiments were conducted to measure changes in ruminal fermentation and animal performance when crude glycerol was added to diets. For the continuous culture experiment (n = 6) diets consisted of four levels of crude glycerol (0, 5, 10 and 20%) that replaced corn grain. Dry matter and organic matter digestibility decreased linearly (P < 0.05) when crude glycerol levels increased in the diet and no effect was observed for CP and NDF digestibility. Total VFA concentration and ammonia did not change (P > 0.05) due to crude glycerol level. Microbial efficiency increased quadratically (P = 0.012) as crude glycerol level increased, while microbial N flow did not differ (P = 0.36) among treatments. As crude glycerol increased in the diet crude glycerol digestibility decreased (P < 0.05). Seventy-two crossbred steer calves (250 ± 2.0 kg) were assigned to four treatments: 0, 5, 10 and 20% crude glycerol that replaced corn grain. Animals were fed for a total of 150 days. No differences (P = 0.08) between treatments were measured for DMI. Average daily gain and GF responded quadratically (P < 0.05), with 10% crude glycerol resulting in highest values. In the second in vivo experiment, one hundred crossbred steer calves (300 ± 2.0 kg) were assigned to five treatments: 0, 5, 10, 12.5 or 15% crude glycerol replaced corn grain. Calves were fed for a total of 135 days. No significant differences (P > 0.05) were measured in growth performance. For experiment three, one hundred heifer calves (270 ± 2.0 kg) were assigned to four treatments: 0, 5, 10, or 20% crude glycerol that replaced hay. No differences (P > 0.05) were measured in animal performance. We concluded that crude glycerol addition to a diet did not negatively affect ruminal fermentation, and addition of up to 20% in concentrate and hay-based diets should not affect performance or carcass characteristics.

Engineered zinc finger nucleases (ZFN) are rapidly gaining popularity as a means to enhance the rate and specificity of DNA modifications in plant and animal cells. Repair-mediated gene modification by ZFN is driven by introducing DNA double strand breaks via a non-specific nuclease domain linked to a sequence-specific zinc finger nucleotide recognition domain. This review examines the use of ZFN to produce genetically modified swine, and the potential of this technology for the future. Pigs are a well established model for human health and disease. By combining conventional gene targeting methods with somatic cell nuclear transfer (SCNT), several genetically modified pig models have been produced. These conventional techniques are inefficient in mammalian somatic cells and provide little control over the site-specificity and rate of exogenous DNA integration. The use of engineered ZFN that bind and cleave genomic DNA at specific loci can enhance targeting efficiencies by orders of magnitude. Recent publication of the first genetic modification in pigs by combining ZFN technology with somatic cell nuclear transfer has opened the door to genome targeting with a precision that was not previously possible in a large animal model. Since that time, model pigs with selective knockout of endogenous genes have been produced. This review will examine the use of ZFN to generate these pig models and the potential of ZFN to accelerate the production of genetically modified pigs of agricultural and biomedical importance. Current methods of ZFN design, important considerations for their safe and effective use in modification of the swine genome, and future innovative applications of this technology in pigs will be discussed.

Increasing feed costs and the desire to improve environmental stewardship have stimulated renewed interest in improving feed efficiency of livestock, including that of U.S. dairy herds. For instance, USDA cost projections for corn and soybean meal suggest a 20% increase over 2010 pricing for a 16% protein mixed dairy cow ration in 2011, which may lead to a reduction in cow numbers to maintain profitability of dairy production. Furthermore, an October 2010 study by The Innovation Center for U.S. Dairy to assess the carbon footprint of fluid milk found that the efficiency of feed conversion is the single greatest factor contributing to variation in the carbon footprint, due to its effects on methane release during enteric fermentation and from manure. Thus, we are conducting research in contemporary U.S. Holsteins to identify cows most efficient at converting feed to milk in temperate climates using residual feed intake (RFI), a measure used successfully to identify the most efficient beef cattle at converting feed to gain. Residual feed intake is calculated as the difference between predicted and actual feed intake to support maintenance and production (e.g., growth in beef cattle, or milk in dairy cattle). Heritability estimates for RFI in dairy cattle reported in the literature range from 0.01 to 0.38. Selection for a lower RFI phenotype can reduce feed intake, methane production, nutrient losses in manure, and visceral organ weights substantially in beef cattle. We have estimated RFI during early lactation (i.e., to 90 d in milk) in the Beltsville Agricultural Research Center Holstein herd and observed a mean difference of 3.7 kg/d (P < 0.0001) in actual DMI between the efficient and inefficient groups (± 0.5 SD from the mean RFI of 0), with no evidence of differences (P > 0.20) in mean BW, ADG, or energy-corrected milk exhibited between the 2 groups. These results indicate promise for using RFI in dairy cattle to improve feed conversion to milk. Previous and current research on the use of RFI in lactating dairy cattle are discussed, as well as opportunities to improve production efficiency of dairy cattle using RFI for milk production.

The beef cattle industry relies on utilization of high forage diets to develop replacement females, maintain the cow herd, and sustain stocker operations. Forage quantity and quality fluctuate with season and environmental conditions. Depending on class and physiological state of the animal, a forage diet may not always meet nutritional requirements, resulting in low ADG or weight loss if supplemental nutrients are not provided. It is important to understand the consequences of such weight loss and the economics of providing supplementation to the beef production system. Periods of limited or insufficient nutrient availability can be followed by periods of compensatory gain once dietary conditions improve and may be of less impact in breeding animals where actual weight is not as important as it is in animals destined for the feedlot, provided reproductive efficiency is not compromised. A rapidly evolving body of literature is also demonstrating that nutritional status of cows during pregnancy can affect subsequent offspring development and production characteristics later in life. Maternal stimulus during critical periods of fetal development having long-term implications on offspring is the concept of fetal programming. Depending on timing, magnitude, and duration of nutrient limitation or supplementation, it is possible that early measures in life, such as calf birth BW, may be unaffected while measures later in life, such as weaning BW, carcass characteristics, and(or) reproductive traits may be influenced. This body of research provides compelling evidence of a fetal programming response to maternal nutrition in beef cattle. Future competitiveness of the U.S. beef industry will continue to be dependent on the utilization of high forage diets to meet the majority of nutrient requirements. Consequences of nutrient restriction or supplementation must be considered not only on individual animal performance but also the developing fetus and its subsequent performance throughout life.

A 5 x 5 Latin square design trial was conducted to evaluate rumen fermentation and apparent nutrient digestibility in 5 rumen cannulated heifers (420±6 kg) fed a barley-based finishing diet supplemented with 20 or 40% wheat or corn dried distillers grains with solubles (DDGS). The composition of the control diet was 88.7% rolled barley grain, 5.5% supplement and 5.8% barley silage (DM basis). Increasing the level of corn DDGS in the ration resulted in a quadratic decrease in DMI (P = 0.04) and OM intake (P = 0.05). Rumen pH, duration and area under rumen pH thresholds of 5.8 or 5.5 were not affected (P > 0.05) by treatment. Wheat DDGS inclusion resulted in a quadratic increase (P = 0.05) in pH area below the cutoff value of 5.2 with the most pronounced effect at 20% inclusion. Wheat DDGS linearly increased (P = 0.01) rumen ammonia-nitrogen (NH₃-N) levels. Increasing the inclusion rate of wheat and corn DDGS resulted in quadratic (P = 0.05) and linear (P = 0.04) decreases in rumen propionate while butyrate increased quadratically (P < 0.01) and linearly (P < 0.01), respectively. Feeding wheat DDGS linearly decreased (P < 0.01) DM and OM digestibility. Corn DDGS inclusion increased the digestibility of ether extract (EE) (P = 0.05; quadratic response) and CP (P <0.01; linear response). Neutral detergent fiber digestibility increased in a linear fashion (P = 0.01) as both wheat and corn DDGS inclusion increased while ADF digestibility increased linearly (P = 0.03) for wheat and quadratically (P = 0.02) for corn DDGS. Increased inclusion level of wheat DDGS resulted in a linear decrease in gross energy digestibility (P = 0.01), while increasing corn DDGS inclusion level linearly increased (P < 0.01) the DE content of the diet. Feeding both wheat and corn DDGS linearly increased (P = 0.01) the excretion of N and phosphorus (P). In summary, replacement of barley grain with up to 40% WDDGS or CDDGS did not mitigate rumen pH conditions associated with mild to moderate acidosis in heifers fed a barley-based finishing diet. Supplementing corn DDGS increased nutrient digestibility of all nutrients and as a result led to higher DE content. Supplementation of wheat DDGS reduced DM and OM digestibility with no effect on DE content. Increased N and P excretion by heifers fed DDGS at 20 or 40% of diet DM presents a challenge for cattle feeders with respect to nutrient management.

To provide further insights into ruminant lipid digestion and metabolism, and into cis-9,trans-11 18:2 synthesis, 12 growing Engadine lambs grazing either mountain pasture (2250 m above sea level; n = 6) or lowland pasture (400 m above sea level; n = 6) were studied. Both pastures exclusively consisted of C₃ plants. Before the experiment, all animals grazed a common pasture for 6 weeks. Grasses and perirenal adipose tissues of the sheep were analyzed for fatty acids by gas chromatography. Stable carbon isotope ratios (¹³C values in vs. Vienna Pee Dee Belemnite standard) were determined in the composite samples by elemental analyzer-isotope ratio mass spectrometry. The ¹³C of the individual fatty acids were measured by gas chromatography-combustion-isotope ratio mass spectrometry. The ¹³C value of the entire mountain pasture grass was –27.5 (SD 0.31) while that of the lowland pasture grass was –30.0 (SD 0.07). This difference was reflected in the perirenal adipose tissues of the corresponding sheep (P = 0.03), even though ¹³C values were lower in the animals than in the grass. The ¹³C values for cis-9 16:1 and cis-9 18:1 in perirenal fat differed between mountain and lowland lambs (P < 0.05). The 16:0 in the adipose tissue was enriched in ¹³C by 5 compared to the dietary 16:0, likely as a result of partly endogenous synthesis. The ¹³C values of cis-9,trans-11 18:2 (cis-9,trans-11 CLA) in the adipose tissue were smaller compared to those of its dietary precursors, cis-9,cis-12 18:2 and cis-9,cis-12,cis-15 18:3; conversely, the ¹³C values of trans-11 18:1 were not, suggesting that large proportions of perirenal cis-9,trans-11 18:2 were of endogenous origin and discrimination against ¹³C occurred during 9-desaturation. The same discrimination was indicated by the isotopic shift between 16:0 and cis-9 16:1 in the mountain grazing group. Furthermore, the ¹³C values of cis-9,trans-11 18:2 were smaller relative to the precursor fatty acids in the mountain lambs than in the lowland group. This result suggests a lower biohydrogenation extent in lambs grazing on mountain grass in comparison to those grazing on lowland grass. This was supported by the smaller cis-9,trans-11 18:2 concentrations in total fatty acids found in the adipose tissues of the lowland lambs (P < 0.001). The results of this study demonstrate that natural differences between ¹³C values of swards from different pastures and the adipose tissue fatty acids could be used as tracers in studies of lipid metabolism in ruminants.

Dietary supplementation of stearidonic acid (SDA; 18:4n-3) has been considered to be a possible strategy to increase n-3 unsaturated fatty acid content in ruminant products, however little is known about its metabolism in the rumen. In vitro batch incubations were carried out with bovine ruminal digesta to investigate the metabolism of SDA and its biohydrogenation products. Incubation mixtures (4.5 mL) contained 0 (SDA0, control), 0.25 (SDA0.25), 0.50 (SDA0.5), 0.75 (SDA0.75), 1.00 (SDA1), 1.25 (SDA1.25), and 1.50 (SDA1.5) mg SDA supplemented to 33 mg (DM basis) commercial total mixed ration (TMR) based on corn silage, for dairy cows, were incubated for 72 h at 39 °C. The content of most fatty acids in whole freeze-dried cultures was affected by SDA supplementation. Branched-chain fatty acids decreased linearly (P < 0.01), and odd-chain fatty acids decreased quadratically (P < 0.01), particularly from SDA1 and above, whereas most C18 fatty acids increased linearly or quadratically (P ≤ 0.04). Stearidonic acid concentrations at 72 h were very low, < 0.6% of total fatty acids and ≤ 0.9% of added SDA, in all treatments. The apparent biohydrogenation of SDA was extensive, but it was not affected by SDA concentration (P > 0.05). Biohydrogenation followed a pattern similar to other C18 unsaturated fatty acids up to SDA1, stearic acid (18:0) and vaccenic acid (18:1 trans-11) being the major fatty acids formed, the latter increasing 9 fold in SDA1. At higher inclusion rates, 18:0 and 18:1 trans isomers decreased (P ≤ 0.03), accompanied by increases in unidentified 18:3 and 18:4 isomers (P = 0.02), suggesting that the biohydrogenation pathway was inhibited. The present results indicate clearly that SDA was metabolized extensively, with numerous 18:4 and 18:3 products formed en route to further conversion to 18:2, 18:1 isomers and 18:0.

The impact of diet deprivation and subsequent over-allowance in prepubertal gilts on their mammary development and mammary gene expression at the end of gestation and their lactation performance over 2 parities was determined. Seventy-seven gilts were reared under a conventional (control, CTL; n = 41) or an experimental (treatment, TRT; n = 36) dietary regimen. The experimental regimen provided 70 (restriction diet, R) and 115% (over-allowance diet, OVER) of the protein and DE contents provided by the CTL diet. Experimental diets were fed ad libitum starting at 27.7 ± 3.4 kg BW as follows: 3 wk R, 3 wk OVER, 4 wk R, and 4 wk OVER. All gilts were bred and 34 were slaughtered on d 110 of gestation (18 CTL and 16 TRT) to collect mammary tissue for compositional analyses and gene expression measurements. Remaining gilts (23 CTL and 20 TRT) were maintained for 2 parities and litter performance data were obtained. Blood samples for hormonal and metabolite assays were obtained on d 110 of gestation from all sows slaughtered at that time and from 14 sows per treatment on d 2 and 17 of lactation in the first parity. Milk samples were obtained from these same sows on d 17 of lactation in both parities. There was a tendency for mammary parenchymal tissue to contain less protein in TRT than CTL sows (P < 0.10) and relative mRNA abundance of the signal transducer and activator of transduction 5B gene was increased in parenchyma from TRT sows (P < 0.05). Circulating prolactin (P < 0.05) and milk lactose concentrations (P < 0.01) were lower, whereas milk protein content was greater (P < 0.05) in TRT sows than CTL sows on d 17 of lactation. Nevertheless, growth rate of suckling piglets over the first 2 parities was unaffected by treatment. In conclusion, the use of a diet deprivation and over-allowance regimen in the growing-finishing period did not have beneficial effects on mammary gene expression or on sow and piglet performance.

The role of the dairy cow is to help provide high quality protein and other nutrients for humans. We must select and manage cows with the goal of reaching the highest possible efficiency for any given environment. We have increased efficiency tremendously over the years, yet the variation in productive and reproductive efficiency among animals is still quite large. In part this is because of a lack of full integration of genetic, nutritional and reproductive biology into management decisions. However, integration across these disciplines is increasing as the biological research findings show more specific control points at which genetics, nutrition and reproduction interact. An ordered systems biology approach that focuses on why and how cells regulate energy and N use and on how and why organs interact by endocrine and neurocrine mechanisms will speed improvements in efficiency. More sophisticated dairy managers will demand better information to improve the efficiency of their animals. Using genetic improvement and proper animal management to improve milk productive and reproductive efficiency requires a deeper understanding of metabolic processes during the transition period. Using existing metabolic models, we can design experiments specifically to integrate new data from transcriptional arrays into models that describe nutrient use in farm animals. A systems modeling approach can help focus our research to make faster and large advances in efficiency, and show directly how this can be applied on the farms.

A study was conducted to compare growth performance and behaviors of group-farrowed pigs with confinement-farrowed pigs. A total of 216 pigs at 8 wk of age were used with equal number of group-farrowed or confinement-farrowed pigs from one farrowing batch. Group-farrowed pigs were farrowed in bedded, individual pens, and mingled into a group of 8 litters at 12 (± 1.3) d of age. Pigs were weaned at 33 (± 1.3) d, and remained in the farrowing room until 8 wk of age. Confinement-farrowed pigs were farrowed in farrowing crates. At weaning (32 ± 2.0 d of age), confinement-farrowed pigs were mixed and moved to pens of 9 pigs in a confinement nursery and remained there until 8 wk of age. At 8 wk of age, pigs from the two housing systems were allocated into 24 pens of 9 pigs in a confinement growing-finishing barn, with 12 pens from each of the housing systems. Within farrowing system, pigs from different groups or pens were mixed upon entering the growing-finishing barn. Individual weight was recorded at the allotment (wk 0) to the growing-finishing barn, and every 2 wk thereafter for 14 wk. Feed intake and G:F were monitored on a pen basis every 2 wk between wk 0 and wk 14 of the study period. Behaviors of pigs were video-recorded in 6 pens of each housing treatment for 24 h on the day of mixing (d 0), d 7, and d 14 after mixing in the finisher barn. The video-recordings were scanned at 5-min intervals to calculate behavioral time budgets for lying, standing, eating, drinking, and belly nosing. Data were analyzed by using the Proc Mixed model of SAS with repeated measures. Compared with confinement-farrowed pigs, group-farrowed pigs spent more time lying (85.7% vs. 82.7%, SE = 0.75; P < 0.001) and belly nosing (0.05% vs. 0.02%, SE = 0.019; P < 0.05), and less time standing (5.8% vs. 7.5%, SE = 0.49; P < 0.01) and eating (7.3% vs. 9.3%, SE = 0.40; P < 0.001). The difference in behavioral time budgets was associated with differences in performance of pigs from the two housing systems. Group-farrowed pigs exhibited greater ADG (866 vs. 814 g, SE = 10.3; P < 0.01) for the initial 2 wk after mixing, less ADFI (2,004 vs. 2,188 g, SE = 42.5; P < 0.05) and improved G:F (0.431 vs. 0.393, SE = 0.0078; P < 0.01) for the entire 14-wk period of the study than confinement-farrowed pigs. These results suggest that group-farrowed pigs were more efficient in utilizing dietary energy for weight gain by lying more, and standing and eating less during the growing and finishing period than confinement-farrowed pigs.

This study was conducted to determine the effects of dietary crude glycerol and dried distillers grains with solubles (DDGS) on growing-finishing pig performance, carcass characteristics, and carcass fat quality. We hypothesized that because dietary crude glycerol has been observed to increase carcass saturated fatty acids, it might ameliorate the negative effects of DDGS on fat quality. The 97-d study was conducted at a commercial swine research facility in southwestern Minnesota with 1,160 barrows (initial BW = 31.0 ± 1.1 kg). Pigs were blocked by initial BW, and pens were randomly allotted to 1 of 6 dietary treatments with 7 replications per treatment. Treatments were arranged in a 2 x 3 factorial with main effects of crude glycerol (0, 2.5, or 5%) and DDGS (0 or 20%). All corn-soybean meal-based diets contained 3% added fat (choice white grease). There were no glycerol x DDGS interactions for any response criteria evaluated. Increasing dietary glycerol did not affect finishing pig growth performance. Adding 20% DDGS to the diet did not affect ADG; however, finishing pigs fed diets with added DDGS had greater (2.47 vs. 2.41 kg/d; P = 0.02) ADFI and poorer (0.39 vs. 0.40; P = 0.01) G:F than pigs not fed DDGS. Feeding increasing dietary glycerol or 20% DDGS did not affect carcass characteristics. For carcass fat quality, feeding 20% DDGS resulted in decreased (P < 0.01) palmitic and oleic acids, total saturated fatty acids, and total MUFA and increased (P < 0.01) linoleic, total PUFA, total unsaturated fatty acids, and iodine value (IV) in jowl fat, belly fat, and backfat. Increasing dietary crude glycerol increased myristic acid (linear, P < 0.05) and MUFA (quadratic, P < 0.05) in jowl fat and increased (quadratic, P < 0.05) oleic acid and MUFA in backfat. In conclusion, feeding 20% DDGS to finishing pigs increased ADFI, reduced G:F, and increased carcass fat IV, whereas feeding crude glycerol did not influence growth performance, carcass characteristics, and had a minor influence on fatty acids of carcass fat. Both of these biofuel coproducts can be used in combination without affecting finishing pig performance or carcass traits; however, feeding crude glycerol did not fully mitigate the increased unsaturation of carcass fat observed when feeding DDGS.

The objective of this experiment was to determine if dietary inclusion of fish meal would increase plasma and luteal tissue concentrations of eicosapentaenoic and docosahexaenoic acids. Seventeen nonlactating Angus cows (2 to 8 yr of age) were housed in individual pens and fed a corn silage-based diet for approximately 60 d. Diets were supplemented with fish meal at 5% DMI (a rich source of eicosapentaenoic acid and docosahexaenoic acid; n = 9 cows) or corn gluten meal at 6% DMI (n = 8 cows). Body weights and jugular blood samples were collected immediately before the initiation of supplementation and every 7 d thereafter for 56 d to monitor plasma -3 fatty acid composition and BW. Estrous cycles were synchronized using 2 injections of PGF_2α administered at 14-d intervals. The ovary bearing the corpus luteum was surgically removed at midcycle (between d 10 and 12) after estrus synchronization which corresponded to approximately d 60 of supplementation. The ovary was transported to the laboratory and approximately 1.5 g of luteal tissue was stored at -80°C until analyzed for -3 fatty acid content. Initial and ending BW did not differ (P > 0.10) between cows supplemented with fish meal and those with corn gluten meal. Plasma eicosapentaenoic acid was greater (P < 0.05) beginning at d 7 of supplementation and docosahexaenoic was greater (P < 0.05) beginning at d 14 of supplementation for cows receiving fish meal. Luteal tissue collected from fish meal-supplemented cows had greater (P < 0.05) luteal -3 fatty acids and lower (P < 0.05) arachidonic acid and -6 to -3 ratio as compared to tissue obtained from cows supplemented with corn gluten meal. Our data show that fish meal supplementation increases luteal -3 fatty acid content and reduces available arachidonic acid content, the precursor for PGF_2α. The increase in luteal -3 fatty acids may reduce PGF_2α intraluteal synthesis after breeding resulting in increased fertility in cattle.

Bucklings (n = 275) from a complete diallel of Boer, Kiko, and Spanish meat goats were harvested at 7 mo of age (4 mo post-weaning) to evaluate genetic effects on carcass yield. Breed of sire did not affect (P > 0.05) live, carcass, and primal weights. Conversely, breed of dam was a consistently significant source of variation for carcass weight traits. Kiko dams produced kids with heavier (P < 0.05) live, carcass, and primal weights than Boer dams. Weights from Spanish dams were intermediate of Boer and Kiko with the significance of differences varying by trait. Dressing percent was affected (P < 0.01) by breeds of sire and dam. Kids of Boer sires had lower (P < 0.05) dressing percents than kids of Kiko and Spanish sires. Dressing percent was also lower (P < 0.01) from Boer dams than from Kiko dams; Spanish dams were intermediate and did not differ from Boer or Kiko. Subjective conformation scores for muscularity were affected (P < 0.01) by breeds of sire and dam. Boer-sired kids had better (P < 0.01) live scores than Kiko-sired kids. Progeny of Boer dams had better (P < 0.05) live scores than progeny of Spanish dams. Boer-sired kids also had better carcass scores (P < 0.05) than Kiko-sired and Spanish-sired kids. Breed differences for primal cut proportions were negligible. Proportional boneless meat yields did not vary (P > 0.05) by breeds of sire or dam. Direct effects of Boer were negative for carcass weight, dressing percent, and shoulder weight and positive for proportional leg weight. Direct effects of Kiko were positive for carcass weight and shoulder weight and negative for proportional leg weight. Direct effects of Spanish did not differ from 0 for any trait tested. Heterosis levels were similar among breed pairings. Heterosis was substantial (P ≤ 0.05) for live, carcass, and primal weights (5 to 9%) but not for dressing percent, proportional boneless meat yield, or primal weight proportions (< 2%). Significant genetic variation was observed among goat breeds for carcass yield traits. Dam breed was more influential than sire breed. Boer germplasm was not superior to Kiko or Spanish germplasm for carcass yield when semi-intensively managed on humid, subtropical pasture. Results emphasize the importance of comparative breed evaluations to provide industry with reliable information on carcass yield among goat genotypes.

The objective of the study was to examine whether residual feed intake (RFI) reranking exists between 2 consecutive periods in replacement heifers fed the same diet. The study collected feed intake and BW data from 190 crossbred heifers over a 3-yr period (61 in 2007; 68 in 2008; and 61 in 2009) during the winter-spring season. The heifers were fed a roughage-based diet (90% barley silage and 10% rolled barley grain) throughout the feeding trial, which was broken down into 2 feeding periods with ADG of 0.94 kg d^-1 and 0.90 kg d^-1, in the first and second periods, respectively. The RFI was calculated for the entire period using different models, which included ADG, mid-metabolic BW, body composition, and feeding activity. Gain:feed ratio (G:F) and Kleiber ratio (KR) were also calculated. Rank correlations among the RFI calculated from different models were obtained, as well as rank correlations between the 2 feeding periods for the feed efficiency measures. Including body composition and feeding activity only improved the R² by 1 to 5%. The rank correlations among the different models were high (90 to 95%) for RFI calculated for the entire feeding period. However, the RFI calculated within the second feeding period had greater rank correlation with the RFI calculated from the entire feeding period. Compared to G:F and KR, RFI gave lesser reranking between periods 1 and 2. About 49% of the heifers maintained their RFI class while 51% of the heifers had a different RFI-class in period 2. Furthermore, 41% of the heifers changed their RFI in period 2 by < 0.5 SD while the rest of the heifers changed by ≥ 0.5 SD. These results indicate that reranking exists in heifers despite receiving the same diet in the 2 feeding periods and that the reranking may be more serious in the heifers (28%) with extreme RFI performances in each period.

The impact of diet deprivation and subsequent over-allowance on the metabolite status, mammary development, and mammary gene expression in prepubertal gilts was determined. Forty-seven gilts were reared under a conventional (control, CTL; n = 23) or an experimental (treatment, TRT; n = 24) dietary regimen. The later regimen (consisting of diet deprivation and subsequent over-allowance) provided 70 (restricting diet, R) and 115% (over-allowance diet, OVER) of the protein and DE contents provided by the CTL diet. Experimental diets were fed ad libitum starting at 27.7 ± 3.4 kg BW as follows: 3 wk R, 3 wk OVER, 4 wk R, and 4 wk OVER. At each diet change, weights and individual feed intakes were measured, and blood samples for metabolite and IGF-I assays were obtained. Some gilts (11 CTL and 12 TRT) were slaughtered on d 235 (after reaching puberty) to collect mammary tissue for compositional analyses and measures of gene expression. Weight gain (P < 0.01) and G:F (P < 0.05) of gilts were reduced during each period with the R diet; however, there was no compensatory growth during the periods when the OVER diet was fed periods. Feeding the R diet reduced concentrations of urea and IGF-I (P < 0.01) and feeding the OVER diet increased FFA (P < 0.01) and glucose (P < 0.10) in TRT gilts compared with CTL gilts. The TRT gilts had less parenchymal tissue (P < 0.05) and tended to have less total parenchymal fat and protein (P < 0.1) than CTL gilts. The mammary mRNA relative abundance of the signal transducers and activators of transduction 5B was lower in TRT than CTL gilts (P < 0.05). In conclusion, the diet deprivation and over-allowance regimen used in the growing-finishing period did not have beneficial effects on mammary development after puberty. In fact, a detrimental effect was observed.

The development of replacement heifers is a major economic investment for all beef and dairy operations. The costs associated with heifer development cannot be recovered if heifers do not conceive and remain productive in the herd; therefore, heifers need to conceive early in the breeding season or risk being culled. Previous research has reported up to a 21% increase in fertility from a heifer’s pubertal estrus to the third estrus. The use of reproductive tract scores to determine pubertal status has demonstrated that peripubertal and pubertal heifers have increased pregnancy success to estrous synchronization compared with heifers that were prepubertal. The development of RIA has allowed accurate measurement of peripheral blood hormone concentrations associated with the pubertal process and lutea formation. This basic knowledge has increased our understanding of the mechanisms that control puberty in heifers. In addition, understanding the hormonal changes that occur during the estrous cycle has allowed for the development of estrous synchronization protocols that result in increased control of follicular growth, regression of luteal tissue, and ovulation. Transrectal ultrasonography has increased our understanding of follicular waves; this understanding led to research investigating the endocrine regulation of follicular waves and development of methods to synchronize follicular waves for purposes of fixed-time AI. Current topics of research include the effect of antral follicle count on fertility and the effect of maternal nutrition (on the fetus in utero) on subsequent reproductive potential of a heifer (i.e. fetal programming). Advancements in genomic technologies will likely provide a powerful tool for selecting heifers at birth that will have a high probability of being reproductively successful if managed correctly. Therefore, knowledge gained through basic research on factors that control puberty has improved and will continue to improve heifer development and fertility.

Few diseases in modern pets are diet- induced. One possible exception to this is obesity, which is ultimately caused by consuming more calories than needed by the dog or cat. While fat is the most concentrated and efficiently stored source of calories, and protein least so, an excess of calories from any source will contribute to adiposity. Obesity is an excess of body fat sufficient to result in impairment of health or body function. In people, this is generally recognized as 20 to 25% above ideal bodyweight. This degree of excess is important in dogs as well. A lifelong study in dogs showed that even moderately overweight dogs were at greater risk for earlier morbidity; these dogs required medication for chronic health problems sooner than their lean-fed siblings. The average difference in body weight between groups was approximately 25%. Obese cats also face increased health risks, including an increased risk of arthritis, diabetes mellitus, hepatic lipidosis, and early mortality. The risk for development of diabetes increases about 2 fold in overweight cats and about 8 fold in obese cats. Altered adipokine secretion appears to be an important mechanism for the link between excess body weight and so many diseases. Once considered to be physiologically inert, adipose tissue is an active producer of hormones, such as leptin and resistin, and cytokines, including many inflammatory cytokines such as tumor necrosis factor alpha (TNFα), interleukins 1β and 6, and C-reactive protein. The persistent, low-grade inflammation secondary to obesity is thought to play a causal role in chronic diseases such as osteoarthritis, cardiovascular disease, diabetes mellitus, and others. For example, TNFα alters insulin sensitivity by blocking activation of insulin receptors. In addition, obesity is associated with increased oxidative stress, which also may contribute to obesity-related diseases. Management of obesity involves nutritional modification as well as behavioral modification. Increased protein intake combined with reduced calorie intake facilitates loss of body fat while minimizing loss of lean body mass. Limiting treats to 10% of calorie intake, and increasing exercise both aid in successful weight management.

This study was carried out to identify single nucleotide polymorphisms (SNPs) associated with fatness traits on pig chromosome 6. In total, 11,067 putative genomic variations were detected in 125 complete bacterial artificial chromosome sequences corresponding to the region between SW2098 and SW1881, which harbors multiple quantitative trait loci (QTL) affecting intramuscular fat content (IMF) and backfat thickness (BFT). Among 173 putative SNPs validated by MassArray, 120 SNPs were used in an association study on 541 offspring produced by a cross of Korean native pig and Landrace breeds. The significance level of each SNP was determined using single marker regression analysis. Further, significant threshold values were determined using a false discovery rate. Nine out of 120 SNPs showed significant effects on BFT and/or IMF. Of the nine significant SNPs, four were significantly associated with IMF, seven were significantly related to BFT, and two SNPs (Kps8172 and Kps6413) showed significant effects on both traits. Moreover, multiple regression analysis considering all significant SNPs was used to correct spurious false positives due to linkage disequilibrium. Consequently, only one SNP (Kps6413) was significant for IMF, whereas four SNPs including Kps6413 showed significant effects on BFT. The significant SNPs had generally additive effects and on average explained 1.72% of the genetic variation for IMF and 3.92% for BFT, respectively. These markers can potentially be applied in pig breeding program for improving IMF and BFT traits after validation in other populations.

Many horse owners find round bales convenient, less labor intensive and more affordable than other hay types, but report an inability to control horse weight gain and excessive hay waste. The objectives were to compare hay waste, hay intake and payback of nine round-bale feeders and a no-feeder control when used during horse feeding. Nine round-bale feeders were tested: Cinch Net, Cone, Covered Cradle, Hayhut, Hay Sleigh, Ring, Tombstone, Tombstone Saver and Waste Less. Each feeder design was placed on the ground in a dirt paddock. Five groups of five horses were fed in rotation for a 4-d period with each feeder. Every fourth day, groups were rotated among paddocks and a new round bale was placed in each feeder. In the five paddocks used, five feeders were installed for d 1 through 20, and the remaining four feeders and no-feeder control were installed for d 21 through 40. Groups of horses were sequentially assigned to feeders using two 5 x 5 Latin Squares, the first for d 1 through 20, the second for d 21 through 40. Horse groups of similar age, weight, breed, and gender were formed from 25 Quarter Horse and Thoroughbred geldings and open mares (means: 11 yr; 541 kg of BW). Hay on the ground surrounding the feeder was collected daily, dried and weighed. The total amount of hay removed around each feeder for a 4-d period was considered waste. Dry matter intake was estimated as the difference between hay disappearance and waste. Number of mo for the reduction in waste to repay feeder cost (payback) were calculated using hay valued at $110/t, and improved feeder efficiency over the control. Feeder design did not affect hay intake (P > 0.05); all feeders resulted in an estimated hay intake of 2.0 to 2.4% BW; the no-feeder control resulted in a reduced intake of 1.3% BW (P = 0.001). Mean % hay waste differed among feeders (P < 0.001); Waste Less, 5%; Cinch Net, 6%; Hayhut, 9%; Covered Cradle, 11%; Tombstone Saver, 13%; Tombstone, Cone, and Ring, 19%; Hay Sleigh, 33%; and no-feeder control, 57%. Feeder design also affected payback (P < 0.01). The Cinch Net paid for itself in less than 1 mo; Tombstone and Ring, 2 mo; Hayhut and Tombstone Saver, 4 mo; Hay Sleigh,5 mo; Waste Less, 8 mo; Cone, 9 mo; and Covered Cradle, 20 mo. Round-bale feeder design affected hay waste and payback, but not estimated hay intake or weight change during horse feeding.

The objective of this study was to determine the optimal postmortem aging period and nutrient composition for Beef Value Cuts of the round. Forty USDA Select and 40 premium USDA Choice beef carcasses were selected from a commercial beef packing plant in Colorado over a 12-week period. The bottom and inside rounds were collected from both sides of each carcass for further fabrication into the following muscles: Adductor, Gastrocnemius, Gracilis, Pectineus, and Superficial digital flexor. Each pair of muscles were cut into seven steaks and randomly assigned to one of the following aging periods: 2, 4, 6, 10, 14, 21, and 28 days, and placed in refrigerated storage (2°C, never frozen). Upon completion of the designated aging period, steaks were removed from storage, cooked to a peak internal temperature of 72°C, and evaluated using Warner-Bratzler shear force (WBSF). A two-way interaction was detected (P < 0.05) between individual muscle and postmortem aging period. The WBSF of all muscles except the Superficial digital flexor decreased with increased time of postmortem aging. Quality grade did not affect (P > 0.05) WBSF values for the Adductor, Gastrocnemius, Pectineus, and Superficial digital flexor muscles. Exponential decay models were used to predict the change in WBSF from 2 to 28 days postmortem (aging response). The Adductor, Gastrocnemius, Select Gracilis, premium Choice Gracilis, and Pectineus required 21, 14, 23, 23, and 25 days, respectively, to complete the majority of the aging response. To determine the nutrient composition of the Adductor, Gastrocnemius, Gracilis, Pectineus, Semimembranosus, and Superficial digital flexor, bottom and inside rounds were collected from 10 USDA Select and 10 premium USDA Choice carcasses and fabricated into the respective muscles, cut into 2.54 cm cubes, frozen (-20°C), and then homogenized. The Adductor, Gracilis, Pectineus, Semimembranosus, and Superficial digital flexor were analyzed for dry matter, moisture, crude protein, and ash percentages. All muscles were evaluated for total lipid, fatty acid and cholesterol composition. When quality grades were combined, all muscles fell into the "extra lean" or "lean" categories specified by USDA guidelines. Results of this study illustrate the potential for Beef Value Cuts of the round to be sold in foodservice operations and retail stores with marketing emphasis being placed on the exceptional leanness and acceptable tenderness of these cuts.

A total of 150 weanling pigs [(Yorkshire x Landrace) x Duroc] with an average BW of 7.22 ± 0.80 kg (21 d of age) were used in a 28-d trial to determine the effects of dietary fructan and mannan oligosaccharides on growth performance, nutrient digestibility, blood profile, and diarrhea score in weanling pigs. Pigs were allotted randomly to 1 of 5 dietary treatments: 1) negative control (NC), basal diet, 2) positive control (PC), NC + 0.01% apramycin (165 mg/kg), 3) NC + 0.1% fructan (FC), 4) NC + 0.1% mannan oligosaccharide source (MO), and 5) NC + 0.05% fructan + 0.05% mannan oligosaccharide source (FM). There were 3 replications per treatment with 10 pigs per pen (5 barrows and 5 gilts). From d 0 to 14, ADG and ADFI of pigs fed the PC, MO, and FM diets were greater (P < 0.05) than pigs fed the NC diet. From d 15 to 28, there were no differences in ADG, ADFI, and G:F. During the overall period (d 0 to 28), pigs fed the MO diet had a greater ADG than pigs fed the NC diet (P < 0.05). Pigs fed the PC and MO diets increased ADFI (P < 0.05) compared with pigs fed the NC diet. However, no differences were detected among dietary treatments in G:F during the overall experimental period. On d 14, the apparent total tract digestibility (ATTD) of DM and N in pigs fed the PC, MO, and FM diets was greater (P < 0.05) than pigs fed the NC diet. The ATTD of DM increased (P < 0.05) in pigs fed the MO and FM diets compared with pigs fed the FC diet. However, at the end of the experiment, pigs fed the FM diet had a greater (P < 0.05) ATTD of DM compared with pigs fed the NC diet. Additionally, there were no differences in IgG, red blood cells, white blood cells, and lymphocyte counts among dietary treatments on d 0, 14, or 28. The diarrhea score in pigs fed the MO diet was reduced (P < 0.05) compared with pigs fed the NC diet. In conclusion, mannan oligosaccharides have beneficial effect on growth performance and nutrient digestibility in weanling pigs. Furthermore, mannan oligosaccharides can decrease diarrhea score in weanling pigs.

The calpain protease system, in particular, μ-calpain is involved in the disassembly of specific myofibrillar proteins, resulting in tenderization of meat postmortem. Given the size, complexity and integral nature of titin to the structure of the sarcomere, it is plausible that the length of a sarcomere may alter the susceptibility of various domains of titin to cleavage by the calpains. Therefore, we hypothesized titin degradation differs in a sarcomere length-dependent manner in beef. Following harvest, beef carcasses were split and sides were either suspended by the Achilles tendon (normal suspension, NS) or by the aitchbone (hip suspension, HS). Immediately following suspension, samples were dissected from the longissiumus dorsi (LM), psoas major (PM), and semitendinosus (ST) muscles to serve as 0 d controls. After 24 h, four steaks were removed from each muscle and randomly assigned to 1, 4, 7, or 10 d aging treatments. Following the assigned aging period, myofibrils were purified for determination of sarcomere length. Warner-Bratzler shear force analysis was also performed to evaluate differences in tenderness. Muscle proteins were solubilized and subjected to SDS-VAGE (vertical agarose gel electrophoresis) to evaluate titin degradation. Sarcomere lengths differed (P < 0.0001) between contralateral muscles of NS and HS carcasses. Quantification of SDS-VAGE gels revealed less (P < 0.05) intact titin in the PM muscle of NS carcasses at each aging period compared with the PM of HS carcasses. No significant differences were detected in the disappearance of intact titin among suspension methods in the LM or ST. These data demonstrate that suspension method alters proteolysis of titin and suggest an increase in sarcomere length may contribute to the susceptibility of titin to postmortem proteolysis in beef.

Breeding standards of most dog breeds specify tolerable ranges of certain conformation traits. In the German shepherd dog (GSD) current means of withers height (WH) and body weight (BW) are close to the upper breed limits. Therefore, strategies to avoid further increase of size and to maximize the proportion of dogs fitting the breeding standard with respect to WH and BW should be compared. Body measurements were available for 14,416 male and 21,612 female GSD from 26,155 litters. WH and body mass index (BMI), i.e. the quotient of BW and squared WH, were considered as direct selection traits. Using information on 17,154 GSD from litters with at least two dogs with conformation data, within litter variances of WH (vWH) and BMI (vBMI) were defined as traits to select for conformational homogeneity of litters. Officially recorded scores of canine hip dysplasia (CHD) of all dogs were used to monitor possible side effects of conformation selection on CHD. Genetic parameters were estimated multivariately in linear animal models using Gibbs sampling. Heritabilities ranged between 0.19 and 0.34 for all traits with additive genetic correlation of -0.11 between WH and vWH and 0.11 between BMI and vBMI. Expected selection response was studied using relative breeding values (RBV) of parents, assuming exclusion of sires and/or dams with RBV larger than 120, and comparing means of WH, BMI and CHD score between offspring of all and selected parents. Concurrent selection for small WH and vWH was found to most efficiently reduce mean WH in males and females while having little impact on CHD distributions. Multiple trait selection for WH, vWH, BMI and vBMI was hindered by the negative genetic correlations between the traits and tended to interfere with improvement of CHD status. Use of RBV for WH and vWH for conformation selection is therefore recommended to maximize breeding success with regard to conformation and conformational homogeneity in the GSD.

Photoperiod, or the daily sequence of light and dark, has dramatic effects on many physiological systems across animal species. Light patterns alter melatonin secretion profiles and, subsequently, the release profiles and circulating concentrations of a number of hormones that influence a variety of physiological responses. Although the impact of photoperiod on reproductive processes is perhaps the most common example, it is often the seasonal aspects of ovulation and anestrus that are considered. However, in cattle, the final phase of reproduction, that is, lactation, is significantly influenced by photoperiod. In contrast to short days (SDPP; 8h light:16 h dark), exposure to long days (LDPP) of 16 to 18 h of light and 6 to 8 h of darkness increases milk yield 2 to 3 kg/d, regardless of the stage of lactation. There is evidence that this LDPP effect is due to increased circulating IGF-I, independent of any effect on GH concentrations. Cows that are housed under SDPP during the dry period have increased mammary growth and produce 3 to 4 kg/d more milk in the subsequent lactation compared with cows on LDPP when dry. While on SDPP, circulating prolactin (PRL) diminishes but expression of PRL receptor increases in mammary, liver, and immune cells. Moreover, PRL signaling pathways within those tissues are affected by photoperiod. Further, replacement of PRL to cows on SDPP partially reverses the effects of SDPP on production in the next lactation. Thus, effects on dry cows are mediated through a PRL-dependent pathway. Before maturity, LDPP improve mammary parenchymal accumulation and lean body growth, which lead to greater yields in the first lactation. The accumulated evidence supports the concept that photoperiod manipulation can be harnessed to improve the efficiency of production across the life cycle of the dairy cow.

Thirty-two crossbred lambs (BW = 31.2 ± 4.7 kg; 16 females, 16 males) housed in individual pens were used to investigate the relationship between nutrient supply and taste preferences in ruminants. Experiment 1, determined whether an imbalanced CP supply would alter preferences for feeds containing flavors designed to elicit either umami (U) or a mixture (1/3:1/3:1/3) of umami, sweet, and bitter (M) tastes. Lambs were randomly allocated to either a low (LP; 10.9% CP) or a high (HP; 20.4% CP) CP diet for 21 d. Afterwards, lambs were presented during 21 d with a choice of the same LP or HP diet unflavored (LPC or HPC) or flavored (0.1% as fed) either with U (LPU or HPU) or M (LPM or HPM). Experiment 2 determined the influence of CP status on preference for dietary CP, bitter taste, and sweet taste elicited by sucrose or a non-caloric sweetener. In test 1, 16 lambs previously fed LP or HP for 42 d in Exp. 1, could choose between the HP and LP diets. In test 2, the remaining 16 lambs from Exp. 1 were offered a choice between unflavored LP or HP diets or the same diets flavored (0.066% as fed) with a bitter flavor. In test 3, the 16 lambs from test 1 were offered a choice between an unflavored diet (LP or HP) and the same diet flavored with sucrose (0.2%) or a non-caloric sweetener (0.066%). In Exp. 1, when offered a choice, all lambs showed a preference (P < 0.05) for the unflavored diet except for LP lambs which clearly preferred (P < 0.05) LPU (72% of total DMI) over LPC. However, preference for LPU progressively decreased (P < 0.05) as time of exposure to the choice increased. In Exp. 2 (test 1), lambs previously fed LP progressively increased (P < 0.05) total DMI when presented with LP and HP, whereas consumption was constant for lambs previously fed HP and offered a choice of LP and HP diets. At the onset of test 2, lambs fed LP progressively reduced (P < 0.05) preference for the bitter flavor from 53 to 34%. In test 3, lambs previously fed LP diets consumed less (P < 0.05) sweetener- than sucrose-supplemented diet, whereas lambs previously offered HP diets consumed more sweetener- than sucrose-supplemented diet. In summary, protein-restricted lambs were able to differentiate and increase consumption of U-flavored feeds. However, this increase disappeared over time. These results indicate that lambs are able to sense dietary CP content and modulate short-term consumption of flavored feeds based on their nutrient requirements.

Two experiments were conducted to evaluate effects of corn distillers dried grains with solubles (DDGS) on growth performance and health status of weanling pigs. The first experiment evaluated effects of increasing concentrations of DDGS on growth performance and health of weanling pigs. For Exp. 1, dietary treatments included: 1) control (CTL); 2) 0% DDGS (0% DDGS in Phase 2, and 30% DDGS in Phase 3); 3) 5% DDGS (5% DDGS in Phase 2, and 30% DDGS in Phase 3); and 4) 30% DDGS (Phases 2 and 3). Overall, pigs fed 30% DDGS during Phases 2 and 3 had decreased (22.1 vs. 25.1 and 24.0 kg; P = 0.003) BW compared to CTL pigs and pigs that only received DDGS during Phase 3. In addition, pigs fed 5 or 30% DDGS in Phase 2 had decreased (422.7 or 390.0 vs. 468.2 g; P = 0.003) ADG compared to CTL pigs. However, pigs fed 0% DDGS during Phase 2 had similar BW, ADG, and ADFI compared to CTL pigs. Experiment 2 was conducted to evaluate effects of DDGS, lactose, and their interaction on growth performance and health of weanling pigs. Dietary treatments included: 1) CTL; 2) lactose (20%); 3) DDGS (15%); and 4) lactose + DDGS. Diets of interest were fed during Phase 1 (d 0 to14) and a common diet was fed during Phase 2 (d 14 to 28). Pigs receiving DDGS in Phase 1 had greater ADG (576.2 vs. 534.6 g; P = 0.01) and ADFI (814.9 vs. 751.6 g; P = 0.01) during Phase 2 compared to non-DDGS fed pigs. Pigs receiving lactose during Phase 1 had greater ADG (214.7 vs. 177.2 g; P = 0.01), G:F (741.0 vs. 660.3 g/kg; P = 0.01), and tended to have greater ADFI (289.3 vs. 267.6 g; P = 0.07) during Phase 1 but decreased (537.7 vs. 573.1 g; P = 0.09) ADG during Phase 2. Serum Ig analyses and fecal microbial profiling were conducted in both experiments as indicators of health status. No effects of dietary treatment were observed for serum Ig in either experiment. Fecal microbial profiling resulted in statistically significant effects of dietary treatment with respect to microbial similarity and diversity indices (Exp. 1), and lactic acid producing bacteria (Exp. 2) where main effects of both lactose and DDGS were observed with respect to putative L. reuteri (P < 0.05). Results from Exp. 1 indicate that low concentrations of DDGS early in the nursery phase may negatively affect growth performance; however, growth performance may be maintained when inclusion of high concentrations (30%) of DDGS is delayed until the late nursery period. Results from Exp. 2 indicate that lactose may be incorporated in nursery diets containing DDGS to help maintain growth performance, and DDGS and lactose may affect fecal microbial profiles.

Three studies were performed to examine the effect of starch and protein digestion rate on N retention in grower pigs. In Exp. 1, the glycemic index (GI) of corn, a malting barley, and a slow rumen-degradable barley (SRD-barley) were measured using 6 barrows (BW = 18.0 ± 0.5 kg). The GI of malting barley was greater (P < 0.05) than that of SRD-barley (71.1 vs. 49.4), and the GI of both barley cultivars was lower (P < 0.05) than that of corn (104.8). In Exp. 2, the standardized ileal digestibility (SID) of AA and DE content of the 3 ingredients were determined using 5 ileal-cannulated barrows (BW = 20.7 ± 2.3). The apparent total tract energy digestibility of corn (86.1%) and malting barley (85.7%) were greater (P < 0.05) than SRD-barley (82.3%). The standardized ileal digestibility of Lys was 94.0, 92.6, and 92.4% for corn, malting barley, and SRD-barley, respectively, and did not differ among grains. In Exp. 3, 6 diets were formulated to equal DE (3.40 Mcal/kg), SID Lys (8.6 g/kg), starch (424.9 g/kg), and digestible CP (180.0 g/kg) using values obtained in Exp. 2. Three GI (high, corn; medium, malting barley; and low, SRD-barley) and 2 rates of protein digestion [rapid, soy protein hydrolysate (SPH); and slow, soy protein isolate (SPI)] were tested in a 3 x 2 factorial arrangement with 36 barrows (BW = 32.2 ± 2.5 kg). Pigs were fed 3.0 x maintenance energy requirement daily in 2 meals for 2 wk and housed in metabolic crates to collect feces and urine separately. At the end of the study, intestinal contents were collected from 4 equal-length segments of the small intestine. The percentage of unabsorbed CP in segment 1 relative to dietary CP was greater (P < 0.05) for SPI than SPH diets (170.3 vs. 116.5%). The percentage of unabsorbed starch in segments 1 and 2 was greater (P < 0.05) for SRD-barley than malting barley or corn diets. Nitrogen intake and fecal N excretion were greater (P < 0.05) for pigs fed the malting barley and SRD-barley diets than for pigs fed the corn diet. Urinary N excretion was greater (P < 0.05) for pigs fed SRD-barley diets compared to pigs fed the corn or malting barley diets. Pigs fed slowly digestible starch (SRD-barley; 46.6%) had lower (P < 0.05) net N retention than pigs fed corn or malting barley (54.7 and 54.1%, respectively). In conclusion, slowly digestible starch sources such as SRD-barley may not be suitable to support maximum protein deposition in restricted-fed grower pigs.

The objective of this experiment was to test the hypothesis that differences in the digestibility of total dietary fiber (TDF) among breeds of pigs is influenced by the type of fiber fed and also by the age of the pig. Five Meishan pigs (BW: 77.2 ± 15.2 kg; 5 mo old), 5 light Yorkshire pigs (BW: 80.1 ± 11.2 kg; 4 mo old), and 5 heavy Yorkshire pigs (BW: 102.1 ± 3.5 kg, 5 mo old) were surgically prepared with a T-cannula in the distal ileum. A corn-soybean meal diet (control) was formulated with 5 g•kg^-1 of titanium dioxide as an indigestible marker. Three additional diets were formulated by replacing 30% of the control diet with 30% of distillers dried grains with solubles (DDGS), soybean hulls, or sugar beet pulp, and 1 diet was formulated by replacing 15% of the control diet with 15% pectin. Each group of pigs was allotted to a 5 x 5 Latin square design and pigs were fed the 5 experimental diets during five 14-d periods. Fecal samples were collected on d 12 and ileal digesta were collected on d 13 and 14 of each period. The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of GE and nutrients in each ingredient were calculated using the substitution method. Hindgut disappearance was calculated as the difference between ATTD and AID. When fed the control diet, Meishan pigs, tended (P < 0.10) to have a greater AID of GE and CP (78.6 and 80.3%, respectively) than light (77.0 and 78.9%, respectively) and heavy (75.7 and 76.9%, respectively) Yorkshire pigs, and they had a greater (P < 0.05) ATTD of DM, GE, and carbohydrates (89.2, 89.5, 95.5%, respectively) than light (86.6, 86.4, and 92.4%, respectively) and heavy (87.0, 86.6, and 93.0%respectively) Yorkshire pigs. The ATTD of DM, GE, CP, carbohydrates, and total dietary fiber in DDGS (75.4, 76.3, 81.3, 78.0, and 75.3%, respectively) was greater (P < 0.01) in Meishan pigs than by light (55.7, 58.5, 66.7, 49.2, and 39.0%, respectively) and heavy (59.8, 62.9, 70.0, 51.1, and 55.7%, respectively) Yorkshire pigs. There were no differences among the 3 groups of pigs in the ATTD of GE or nutrients in soybean hulls, sugar beet pulp, and pectin. The hindgut disappearance of DM and carbohydrates in DDGS by Meishan pigs (26.8 and 52.9%, respectively) was greater (P < 0.05) than in the light (10.0 and 22.8%, respectively) and Heavy Yorkshire pigs (12.2 and 20.0%, respectively), but for the other ingredients, no differences in hindgut disappearance among Meishan, light Yorkshire, and heavy Yorkshire pigs were observed. In conclusion, Meishan pigs have a greater ATTD of DM, GE, and some nutrients in corn-soybean meal diets and in DDGS than Yorkshire pigs.

Castration in weaned calves is stressful and affects profitability by reducing ADG and increasing susceptibility to disease. This study evaluated the effect of meloxicam, a non-steroidal anti-inflammatory drug (NSAID), on performance and health of calves received as steers compared with bull calves surgically castrated on arrival at the feedlot. British x Continental bulls (n = 145) and steers (n = 113; BW = 193 to 285 kg) were transported for 12 h in 3 truckloads (d 0), weighed, and randomly assigned to receive either lactose placebo (CONT; 1 mg/kg) or meloxicam (MEL; 1 mg/kg) suspended in water and administered per os, 24 h prior to castration. On d 1, bulls were surgically castrated (CAST) and steers were processed without castration (STR). Combinations of CONT/MEL and CAST/STR were allocated to 24 pens (6 pens per treatment) of 8 to 14 calves each. Pen was the experimental unit. Plasma meloxicam concentrations at the time of castration (d 1) were determined by HPLC-mass spectroscopy. Pen-level ADG, DMI, and G:F were estimated using BW obtained on d 0, d 14, and d 28 and weigh-back of feed. Individual animals were classified as sick based on a depression score of ≥ 2 on a 5-point scale and a rectal temperature of ≥ 39.8°C. On d 0, 1, and 14, calf chute temperament was evaluated using a 4-point scale. Data were analyzed using generalized linear mixed models and survival curve analyses. Castration reduced pen ADG (P < 0.001) and G:F (P < 0.001) from d 1 to d 14, yet no effects were apparent by d 28. For all treatment groups, DMI increased with days on feed (P < 0.0001) but was less in CAST compared with STR calves (P < 0.016) throughout the study. From d 14 to 28, ADG increased in CAST but not STR calves, and G:F decreased in STR but not CAST calves. In CAST calves only, MEL treatment reduced the pen-level first pull rate (P = 0.04) and reduced bovine respiratory disease (BRD) morbidity rate (P = 0.03). The frequency of chute escape behavior was greater on arrival and at castration in CAST vs. STR calves (P < 0.01) but not significantly different at d 14 (P = 0.22). Mean MEL concentrations at castration were no different between treated STR and CAST calves (P = 0.70). Meloxicam administration prior to castration in post-weaning calves reduced the incidence of respiratory disease at the feedlot. These findings have implications for developing NSAID protocols for use in calves at castration with respect to addressing both animal health and welfare concerns.

Jersey cattle are known for producing carcasses with a greater amount of marbling, but they require more days on feed to achieve acceptable market weights as compared with other breeds. The objective of this study was to evaluate the effect of dietary forage level (12 vs. 24% sudangrass:alfalfa hay, DM-basis) in steam-flaked, corn-based finishing diets on carcass characteristics, beef palatability, and retail color stability of steaks from Jersey beef compared to conventionally-fed commodity beef strip-loins (COM) of identified quality (Choice^- and Select⁺). Jersey steers (n = 77) were blocked by weight and randomly assigned to one of the following treatments for a 383-d trial period: Jersey low- 12 (JL; n = 38) or Jersey high- 24% (JH; n = 39) forage, DM-basis. A comparison group was selected from conventionally fed cattle on the same day of harvest as the Jersey treatments and strip loins from USDA Select⁺ (COM; n = 20) and Choice^- (COM; n = 20) were removed for data analysis. Seventy two hours postmortem (PM), strip loins were removed, vacuum-packaged, and aged at 3°C for 18 d PM. Following the aging period steaks from the longissimus muscle were sliced, vacuum-packaged, and frozen (-20°C) until analyzed. Jersey steaks had lower (P < 0.05) Warner-Bratzler shear force (WBSF) values than COM steaks. Trained sensory panelists rated JL greater (P < 0.05) for initial and sustained tenderness and initial juiciness than COM, while JH was intermediate. As expected marbling was greater (P < 0.05) for both JL and JH than COM, and trained sensory panel sustained juiciness, beef flavor intensity, and overall acceptability scores were greater (P < 0.05) for both JL and JH compared to COM; however no differences were reported for consumer tenderness and flavor. Objective color (L*, a*, b*) measurements decreased (P < 0.05) over time across treatments. There were no differences among treatments for L*; however, overall during retail display JL were less (P < 0.05) red (a*) and yellow (b*) than JH and COM. Subjective color scores indicated both JL and JH were less red (P < 0.05) than COM. Steaks from Jersey were equal to and on some measurements more desirable than steaks from COM carcasses for both color stability and palatability. These results suggest that forage level had minimal effects on carcass characteristics and beef palatability. However, feeding a low forage diet decreases input cost and potentially results in a greater valued carcass. Finishing long-fed Jersey steers can meet beef industry expectations with respect to quality grade.

The extracellular matrix (ECM) and specific ECM components can have a major influence on cell growth, development, and phenotype. The influence of the ECM and ECM components on adipogenesis in vivo and in vitro will be reviewed in this paper. Engelbreth-Holm-Swarm (EHS) substratum and laminin per se markedly increased attachment, spreading, and hypertrophy of preadipocytes in serum free primary cultures of porcine adipose tissue stromal-vascular (S-V) cells. Furthermore, primary cultures of S-V cells showed that preadipocytes express ECM components after preadipocyte recruitment. Staining for plant lectins, type IV collagen, and laminin in fetal pig adipose tissue demonstrates that adipocyte reactivity for laminin was strong throughout fetal development and was similar for developing adipocytes and vasculature. However, lectin binding and type IV collagen reactivity of blood vessels preceded that for adipocytes. Therefore, these studies indicated that the ECM and in particular laminin may play a critical role in morphological aspects of preadipocyte development. Specific inhibitors and modulators of collagen synthesis have been used to evaluate the role of collagens in the differentiation of bovine intramuscular preadipocytes (BIP) and other preadipocyte cell lines. Triglyceride accretion of BIP cells was inhibited by a general inhibitor of collagen biosynthesis, whereas specific inhibitors and(or) modulators of type IV collagen inhibited 3T3-L1 cell differentiation. Further study discovered that compared with collagens types I to IV, type V and VI collagens have an important and active role in BIP adipogenesis. The growth of intramuscular bovine adipose tissue may be dependent on collagen newly synthesized and organized by the adipocyte per se. The role of extracellular or ECM proteolysis in regulating adipogenesis also will be reviewed in this paper. Many members of the matrix metalloproteinases (MMP) family are expressed by adipocytes and specific inhibition of MMP-9 greatly reduces adipogenesis in vitro. Possibly, MMP and other proteases regulate turnover of key adipocyte ECM proteins which are involved in the regulation preadipocyte proliferation and differentiation.

Semen characteristics in boars fed organic or inorganic sources of selenium (Se) were assessed in three experiments. Crossbred boars were randomly assigned at weaning to one of 3 dietary treatments: I. basal diets with no supplemental Se (control), II. basal diets with 0.3 ppm supplemental Se from an organic source (Sel-Plex; Alltech, Inc., Nicholasville, KY), and III. basal diets supplemented with 0.3 ppm supplemental Se from sodium selenite. For Experiment 1, semen was collected from boars (n = 10/dietary treatment) on 5 consecutive d at 15 mo of age. Effects of treatment x day were detected for the proportions of progressively motile (P = 0.02) and rapidly moving (P = 0.03) spermatozoa, and measures of sperm velocity, including path velocity of the smoothed cell path (VAP; P = 0.05) and average velocity measured in a straight line from the beginning to the end of track (P = 0.05). Negative effects of day of semen collection on sperm motility were least pronounced in boars fed Sel-Plex. Experiment 2 was conducted when boars were 17 mo of age and semen was collected (n = 10 boars/dietary treatment), diluted in commercially available extenders and stored at 18°C for 9 d. Effects of treatment x day were detected for percentages of motile (P = 0.01) and static (P = 0.01) spermatozoa, amplitude of lateral head displacement (P = 0.02), frequency with which the sperm track crossed the sperm path (P = 0.04), straightness (P = 0.01), and average size of all sperm heads (P = 0.03). In general, sperm cells from boars fed Sel-Plex were better able to maintain motility during liquid storage compared to boars fed sodium selenite. For Experiment 3, semen was collected from boars (n = 6/dietary treatment) at 23 mo of age, and spermatozoa were evaluated at d 1 and 8 post semen collection using in vitro fertilization procedures. There was a tendency for an effect (P = 0.11) of dietary treatment on fertilization rate with Sel-Plex-fed boars having the greatest value (70.7%). The results of this study suggest that there are positive effects of dietary supplementation with Sel-Plex on boar semen characteristics and that organic Se supplementation may help ameliorate the negative effects of semen storage on characteristics of sperm motility.

Studies in numerous species provide evidence that diet during development can mediate physiological changes necessary for puberty. In cattle, several studies have reported inverse correlations between postweaning growth rate and age at puberty and heifer pregnancy rates. Thus, postweaning growth rate was determined to be an important factor affecting age of puberty, which in turn influences pregnancy rates. This and other research conducted during the late 1960s through the early 1980s indicated puberty occurs at a genetically-predetermined size, and only when heifers reach their target weight can high pregnancy rates be obtained. Guidelines were established indicating replacement heifers should achieve 60 to 65% of their expected mature BW by breeding. Traditional approaches for postweaning development of replacement heifers used during the last several decades have primarily focused on feeding heifers to achieve or exceed an appropriate target weight and thereby maximize heifer pregnancy rates. Intensive heifer development systems may maximize pregnancy rates, but not necessarily optimize profit or sustainability. Since inception of target weight guidelines, subsequent research demonstrated that the growth pattern heifers experience prior to achieving a critical target weight could be varied. Altering rate and timing of gain can result in compensatory growth periods, providing an opportunity to decrease feed costs. Recent research has demonstrated that feeding replacement heifers to traditional target weights increased development costs without improving reproduction or subsequent calf production relative to development systems in which heifers were developed to lower target weights ranging from 50 to 57% of mature BW.

For several mammalian species, it has been shown that fetal and early post-natal nutrition has a role in long-term lipid and glucose metabolism of the offspring, and it thus also may have consequences on milk yield in the dairy cow. For instance, high-energy diets during the last weeks of pregnancy may result in elevated glycemia, which in turn, may alter fetal adipose tissue development. However, most research efforts on management and nutrition of dry cows have focused on minimizing metabolic disorders of the post-partum cow without devoting much attention to potential consequences for the offspring. Similarly, nutritional needs for proper placental development and early fetal growth have received little attention, despite the fact that alterations in placental and fetal development may alter expression of genes participating in homeorhesis of the offspring. Therefore, nutrition of the pregnant cow, both while lactating and dry, should also consider aspects of placental and fetal development that may affect health and performance of the progeny. Similarly, newborn calves and young heifers are fed to ensure a particular growth target without compromising mammary development, although data linking post-natal growth targets with future milk yield are scarce. However, milk yield not only depends on mammary development, but also on nutrient partitioning, which is regulated by the endocrine milieu. There are some periods of time during development where nutrition may have long-lasting effects on metabolic function and milk production. For instance, the first months of post-natal life seem to be critical, because recent data from both retrospective and controlled studies indicate that elevated growth rate or plane of nutrition during this phase is positively associated with future milk production. Post-natal growth rate depends on nutrition (a necessary but not sufficient condition) and management (i.e., grouping strategies and housing systems), and thus optimal rearing programs should be designed considering long-term consequences on milk yield.

Our objective in this study is to compare four of the most common bedding materials used by equine operations on the chemical and physical characteristics of composted equine stall waste. Twelve Standardbred horses were adapted to the barn and surrounding environment for 2 wks prior to the start of the study. Groups of three horses were bedded on one of four different bedding types (wood shavings, pelletized wood materials, long straw, and pelletized straw) for 16 h per day for 18 d. Stalls were cleaned by trained staff daily and all contents removed was weighed and stored separately by bedding material on a level covered concrete pad for the duration study. Compost piles were constructed using 3 replicate piles of each bedding type in a randomized complete block design. Each pile was equipped with a temperature sensor, and datalogger. Water was added and piles were turned weekly throughout the 100 d compost process. Initial and final samples were taken, dried and analyzed for dry matter mass, organic matter, inorganic nitrogen (nitrate-N and ammonium-N), electrical conductivity, and soluble (plant-available) nutrients. Data were analyzed using the GLM procedure and means were separated using Fischer’s Protected LSD test (P<0.05). No significant temperature differences were observed among the bedding materials. The composting process resulted in significant reductions in dry matter mass for each of the four bedding materials. The composting process resulted in significant reductions in organic matter and C:N ratio for all four bedding materials. The composted long straw material had higher concentrations of Total Kjeldahl Nitrogen (P < 0.05), nitrate-N (P < 0.05), and ammonium-N (P < 0.05) than the composted wood shavings. This study demonstrated that incorporating a simple aerobic composting system may greatly reduce the overall volume of manure and yield a material that is beneficial for land application in pasture based systems. The straw based materials may be better suited for composting and subsequent land application; however, factors such as suitability of the bedding material for equine use, material cost, labor, and availability must be considered when selecting a bedding material.

Skeletal muscle development and growth is a complex process that involves the interaction of muscle cells with their extracellular environment. Because muscle development involves the interaction of the cell surface and extracellular matrix molecules, research focus has been placed on the proteoglycans. Proteoglycans are macromolecules containing a central core protein with attached carbohydrates, called glycosaminoglycans, that are located at both the cell surface and extracellular matrix. Research focus has been placed on understanding the mechanisms of the membrane-associated heparan sulfate proteoglycans, syndecan-4 and glypican-1, which are both capable of regulating cellular responsiveness to fibroblast growth factor 2 (FGF2). Fibroblast growth factor 2 is a potent stimulator of muscle cell proliferation and a strong inhibitor of differentiation. Studies on syndecan-4 and glypican-1 show that these proteoglycans differentially regulate muscle cell proliferation, differentiation, and cellular responsiveness to FGF2 with syndecan-4 predominantly modulating muscle cell proliferation and glypican-1 modulating differentiation. Site-directed mutagenesis approaches were used to define the effect of the syndecan-4 and glypican-1 covalently attached side chains on their activity. In general, a functional association was found between the glycosaminoglycan and N-glycosylated chains attached to the central core proteins of syndecan-4 and glypican-1 affecting their regulation of muscle cell proliferation, differentiation, and FGF2 responsiveness. Current research efforts are directed at identifying the cellular signaling pathways modulated by syndecan-4 and glypican-1.

Controlled reduction of the connective tissue contribution to cooked meat toughness is an objective that would have considerable financial impact in terms of added product value. The amount of intramuscular connective tissue in a muscle appears connected to its in vivo function, and so reduction of the overall connective tissue content is not thought to be a viable target. However, manipulation of the state of maturity of the collagenous component is a biologically-viable target; by increasing connective tissue turnover, less mature structures can be produced that are functional in vivo but more easily broken down on cooking at temperatures above 60°C, thus improving cooked meat tenderness. Recent work using cell culture models of fibroblasts derived from muscle and myoblasts has identified a range of factors which alter the activity of the principal enzymes responsible for connective tissue turnover, the matrix metalloproteinases (MMP). Fibroblasts cultured from three different skeletal muscles from the same animal show different cell proliferation and MMP activity, which may relate to the different connective tissue content and architecture in functionally different muscles. Expression of MMP by fibroblasts is increased by vitamins which can counter the negative effects of oxidative stress on new collagen synthesis. Preliminary work using in-situ zymography of myotubes in culture also indicates increased MMP activity in the presence of epinephrine and reactive oxidative species. Comparison of the relative changes in MPP expression from muscle cells versus fibroblasts shows that myoblasts are more responsive to a range of stimuli. Muscle cells are likely to produce more of the total MMP in muscle tissue as a whole and the expression of latent forms of the enzymes (i.e., pro-MMP) may vary between oxidative and glycolytic muscle fibers within the same muscle. The implication is that the different muscle fiber composition of different muscles eaten as meat may influence the potential for manipulation their connective tissue turnover.

An experiment was conducted to determine the efficacy of dietary betaine, conjugated linoleic acid or both as growth promotants and carcass modifiers in growing Iberian pigs. Twenty gilts (20 kg BW) were individually penned and fed barley-soybean meal based diets (12% CP, 0.81% lysine and 14.8 MJ ME/kg DM) containing either no added betaine or conjugated linoleic acid (control), 0.5% betaine, 1% CLA, or 0.5% betaine + 1% CLA, at 95% ad libitum energy intake. An additional group of 5 pigs was slaughtered at the beginning of the experiment to obtain initial body composition. At 30 kg BW, a balance experiment was conducted. At 50 kg, pigs were slaughtered and viscera was removed and weighed. Betaine or CLA alone did not affect growth performance. However, betaine + CLA increased ADG (601 vs. 558 g, P = 0.03) and gain relative to ME intake (25.4 vs. 22.2 g/MJ, P = 0.03) compared to control pigs. Digestibility of nutrients and metabolizability of energy did not differ among diets (P = 0.46 to 0.75). Carcass gain numerically increased (388 vs. 424 g/d; P = 0.13) when pigs were fed betaine + CLA compared to the control diet. Protein, water and lean deposition (g/d) increased (19.8, 24.2 and 23.4%, respectively, P < 0.01) in betaine + CLA fed pigs compared to control pigs. Similarly, protein deposition relative to ME intake increased by 28% in betaine + CLA supplemented pigs (P < 0.05). Fat and mineral deposition did not differ among treatments. Carcass protein, water and lean content (g/kg carcass) of pigs fed betaine + CLA supplemented diets tended to increase (P = 0.07 to 0.09) and carcass fat content tended to decrease (P = 0.09). Similarly, estimated composition of carcass gain was affected such that water and lean tended to increase (P = 0.06 to 0.08) while fat tended to decrease (P = 0.08) in pigs fed betaine + CLA supplemented diets. Carcass drip loss numerically increased (P = 0.12) and 10^th-rib backfat at P1 numerically decreased (P = 0.12) in pigs fed betaine + CLA diets. Longissimus muscle area was not altered by treatments (P = 0.49). Liver of pigs fed betaine + CLA diets had increased weight (19%, P < 0.05) compared to control pigs. Overall, dietary supplementation of betaine + CLA increased ADG, protein, water and lean deposition in growing Iberian gilts. There appears to be a synergism of action when betaine and CLA are used together.

Finding appropriate disposal techniques for waste products is one of many challenges facing the poultry processing industry. One waste generated in significant quantities is dissolved air floatation sludge, a product of wastewater treatment. Converting dissolved air floatation sludge into a dry feed product (meal) for incorporation into livestock feed appears to be a viable solution. This meal, called secondary protein nutrients (SPN), is high in protein (45% CP), fat (28% crude fat), and minerals. The protein consists of 85% B₂ and B₃ fractions, which are moderately to slowly degradable in the rumen and therefore may potentially escape ruminal degradation and be available for digestion in the lower gastrointestinal tract. The goal of this research was to evaluate SPN as an alternative to traditional protein sources for ruminants by substituting it on equal N basis for soybean meal in cattle and meat goat diets (0, 25, 50, 75, and 100% for cattle; 0, 20, and 40% for goats). When included in corn silage-based steer diets, increasing SPN resulted in linear and quadratic declines in both DMI and ADG (P < 0.001). Dry matter intake diminished with inclusion rates above 50%, and ADG were reduced after inclusion of SPN reached 25% of added N. Feed efficiency declined linearly (P < 0.001) with each incremental increase in SPN. Addition of up to 40% of added N as SPN in goat diets caused no change in DMI, digestibility of DM or fiber, or N retention. Ruminal VFA concentrations showed little variation in either species. Increasing the proportion of SPN in the feed caused linear declines in ruminal NH₃ in steers (P < 0.001). Increasing SPN in goat diets, however, resulted in only a trend towards reductions of this parameter (P = 0.14). The decreases observed may have resulted from decreasing ruminal protein degradability or increasing fat caused by increasing the proportion of SPN in the feed. Urinary urea N as a percentage of urinary N showed significant declines in urinary urea N as a percentage of urinary N in cattle, but not in goats, over the ranges of SPN offered. These results indicate that SPN can be included in diets for ruminants to supply up to 40% of supplemental N with little negative impact on animal performance.

The aim of this work was to study the effect of recombinant human (rh) FSH and LH on in vitro maturation of pig oocytes in comparison with a conventional hormonal supplement based on equine (PMSG) and human chorionic gonadotropins (hCG) evaluated by the developmental ability of three types of pig embryos obtained by in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) or artificial activation (AA). In Exp. 1, one cumulus oocyte complex (COC) group (A group) was supplemented with 0.1 IU/mL rh-FSH and -LH, and the other group (B group) was supplemented with 10 IU/mL PMSG and hCG. No significant differences in nuclear maturation between A- and B-group were observed (68.5 vs. 71.4 %, respectively). No significant differences between hormonal treatments in cleavage or blastocyst rates of AA, IVF and ICSI embryos were detected. Total cell number of embryos was not significantly different in any experimental group (A: 31.1, 28.5 and 19.8 vs. B: 25.2, 25.5 and 20.6 to AA, IVF and ICSI embryos, respectively). In Exp. 2, effects of different hormonal concentrations of rh-FSH and -LH (0.5, 0.1 and 0.05 IU/mL) in maturation medium on nuclear maturation and in vitro development of embryos obtained by IVF were studied. No effect of different hormonal concentrations on blastocyst rates was observed (8.5, 13.0 and 5.7%, respectively). Blastocyst cell number was not significantly different in any experimental group. In conclusion, results obtained here permit us to substitute PMSG and hCG by rh-FSH and -LH and to produce pig embryos obtained by IVF, ICSI or AA.