According to a study published in the March issue of the Journal of Animal Science, pigs raised in group-farrowing systems may have better long-term body weight gain than pigs raised in confinement-farrowing systems.
In a study of 216 piglets, Y. Z. Li, L. H. Wang and L. J. Johnson from the University of Minnesota West Central Research and Outreach Center found that piglets raised in group-farrowing systems were more efficient in utilizing energy for body weight gain during the finishing period.
Farrowing sows were split into two groups for the study. One group of sows farrowed in individual pens and the piglets stayed in those individual pens until eight weeks of age. The other group of sows farrowed in individual pens, but pen walls were removed after 12 days. Piglets could then mingle between litters.
In their Journal of Animal Science paper, the researchers explained that previous studies had looked at the behavior and welfare of sows in different farrowing systems; “However, effects of group-farrowing systems on piglets that are born and reared in these systems are not usually studied,” wrote the researchers.
This study was also important because the researchers looked how farrowing systems affected piglets later in life. After eight weeks in the different systems, all piglets were moved to group finishing pens. During this period, the researchers found significant differences in behavior and feed efficiency between piglets raised in the two different farrowing systems.
By watching video footage, the researchers spotted several differences in behavior.
“One of major findings in this study was that group-farrowed pigs spent more time lying and less time standing and eating during the first 2 weeks after mixing in the finishing barn,” they wrote.
The researchers thought that more time lying down could mean the piglets from group-farrowing systems spent less time fighting with other piglets. Previous studies had showed that group-farrowed piglets were better adapted to “social challenges” and were less aggressive toward unfamiliar piglets during weaning.
“Pigs reared in complex environments can be less susceptible to stressors,” wrote the researchers.
The group-farrowed piglets also showed better feed efficiency. They had greater average daily gain compared with the piglets from the confinement-farrowing system.
Of course, wrote the researchers, the interactions between behavior, environment and growth performance are complex. They wrote that the confinement-farrowed piglets could have wasted energy by fighting more during the finishing period. Eating habits could also have affect body weight gain. For example, previous studies have shown that the piglets eat faster as group size increases.
This study was titled “Effects of farrowing system on behavior and growth performance of growing-finishing pigs.” It can be read in full at fass.jas.org.
MadelineMS@asas.org / 217-239-3321