Interpretive Summary: Effect of parity and stage of gestation on growth and feed efficiency of gestating sows.
By: Jackie Walling
There is limited research on gestating sows in a commercial setting. Knowledge surrounding feed intake (FI) and body weight (BW) is immense, but factors effecting growth and feed efficiency remain obsolete. A recent article published in the October 2018 Issue of the Journal of Animal Science traveled to a central Nebraskan commercial hog farm to study the effect parity and stage of gestation had on growth and feed efficiency in gestating sows. Additionally, researchers analyzed back-fat and reproductive performance to produce correlations with intake and growth patterns.
As a 149-day study starting in late May and ending in mid-October, 712 hogs completed the study in a group-housed situation with about 260 hogs per pen. Hogs were divided into three groups: Parity 1, Parity 2, and Parity 3+. Each parity group was analyzed over three periods for gestation: Period 1 (d5-39), Period 2 (d40-74), and Period 3 (d75-109). Over 3-4 weeks, when sows reached d5 of gestation, they were added to the group housing and removed upon d112 for farrowing creating a dynamic living situation. Electronic Sow Feeders collected daily intake and weight data during that time to calculate average daily feed intake (ADFI), BW, average daily gain (ADG), and Gain:Feed ratio (G:F). A corn-soybean meal based diet was adjusted to the nutritional needs of each hog. Back-fat was measured on d5 and d112 and reproductive performance traits recorded.
Average daily feed intake for Parity 3+ decreased during period 1 with no difference following d39. Parities 1 and 2 remained higher than Parity 3+, but decreased during Period 1. All parities showed a low ADFI within the first 10 days of entering group housing causing a high degree of variability in Parity 1 gilts. Inconsistent social dynamics and a lack of suggested spatial requirements per pig could have interfered with acclimation to the feeding system resulting in the inconsistency expressed during those initial days.
Body weight increased across all parities due to the development of offspring. Parity 3+ weighed the most throughout, but Parity 1 claimed the highest amount gained. Parity 1 and 2 ADG increased during Period 2 of gestation and decreased in Period 3. Parity 3+ increased progressively. Gain:feed was greatest in Parity 1 with no difference between Parity 2 and 3+. Composition of gain and the feed amount needed for maintenance weight likely influenced ADG and G:F.
Back-fat results showed Parity 1 maintained the same amount throughout gestation while Parity 2 and 3+ gained 1 mm back-fat. Reproductive performance showed Parity 3+ had the greatest volume of total piglets born with Parity 1 greater than Parity 2. Live births were strongest in Parity 3+ while Parity 1 claimed the most mummified.
Multiple correlations between FI, BW, growth, and reproductive performance were found statistically significant and represented graphically within the full article. Most notable was a positive correlation between BW gain and the number of offspring born. The remaining correlations should be recognized, but considered practically weak when evaluating the factors compared. The large sample observed lends itself to providing a solid foundation for evaluating if changes of weight gain and feed efficiency are affected by parities and gestational stages.
To view the full article, visit the Journal of Animal Science.