Date Full Report Received10/08/2015
Date Abstract Report Received10/08/2015
Funded ByNational Pork Board
Sow aggression is a common problem associated with group-housing systems especially during feeding and mixing of sows. Grouped-housed sows establish a social hierarchy upon mixing which often reduces aggressive encounters later-on, however pregnant sows often still engage in aggressive encounters at feeding time due to feed restriction, which can compromise performance, productivity, and well-being of the gestating sow. Realistically, it is not feasible to completely eliminate aggressive encounters among group-kept gestating sows, but it may be plausible to minimize the potential negative effects of aggression on group-kept gestating sows. Therefore, the main objective of this study was to assess the effects of housing small groups (n = 9 sows per pen) of gestating sows in pens at floor-space allowance of 1.7 m2/sow equipped with feeding stall partitions that varied in length (2 ft. vs 6ft.) and fed modified high fiber diet of either 30% wheat middlings-15% soy hulls (Midds-Hulls) or 30% DDGS- 30% corn germ meal (DDGS-GM) on sow well-being. The secondary objective of this study was to more specifically assess the effects that these treatment combinations had on well-being of two lowest ranked sows (submissive) within the group. For the most part, length of feeding partitions and type of high fiber diet had minimal effects on immune, endocrine and performance and productivity, except for improved piglet weaning weight. However, sow social rank played a role in the effects of diet and length of feeding partition on well-being. Specifically, submissive sows housed in pens with long feeding partitions and fed a high fiber diet of DDGS supplemented with corn germ meal weaned the heaviest pigs and received the least number of aggressive encounters. These results imply that if group-pens are not properly designed in terms of adequate floor-space and length of feeding stall partition there are minimal effects on the overall well-being of gestating sows in terms of performance and productivity. Moreover, these data imply that well-being of socially submissive sows may be improved by housing them in pens with longer feeding stalls and feeding them a high-fiber diet. Taken together, these results imply that sow social status is an important factor that should be considered when implementing group pen systems and that housing environment and dietary strategies may be a management tool that can be used to improve at least submissive sow well-being.