In pigs, social behaviors, such as fighting, can affect the performance of all pigs in a group or result in injury or lameness, leading to culling. Expanding genetic selection programs beyond production and health traits to encompass behavior will improve welfare and productivity for group-housed pigs, particularly gestating sows. This study compiled behavioral, genomic, and production data from over 4,000 pigs to better understand the potential for selecting for pigs that are behaviorally adapted for group housing without compromising other traits of interest. We have characterized key aggressive behaviors of pigs in group-housing environments at the nursery, finisher and breeding stage and related these responses to measures of productivity and genetic components for application in breeding programs. Pressing behavior between pigs leads to damaging aggression in a majority of instances, suggesting it could be used as reliable predictor of physical aggression. Immediate prior social experience but not relatedness alone reduces aggression between pigs as they move from the nursery to finisher stage. Social aggression does not appear to be related to fear responses of pigs, nor to their response to human approach or backfat. Aggression, as assessed using lesion scores, is variable between pigs with respect to levels and types of aggression pigs show. Packages and programs have been developed to facilitate genetic analysis of behavioral and performance data, along with improved models for estimating indirect genetic effects. Together the findings and tools generated from the project can be used to improve selection models used in the swine industry to breed pigs better suited to modern husbandry environments, which will enhance the sustainability of pork production in Michigan and the U.S.
Contact information for Dr. Janice Siegford: email = [email protected], phone = 517-432-1388.
