A concern with any type of group housing is the aggression performed when mixing unfamiliar sows into a group, as they compete to form a social hierarchy. Ongoing aggression is another related concern. It is important to understand how different grouping practices influence sow aggression, and how to manage these systems to optimize productivity and wellbeing.
Three grouping treatments were compared in gestation: Control – sows housed in stalls for 35 days after breeding, then moved to static groups; Static – sows mixed into static groups 1-8 days after breeding; and Dynamic – sows mixed into dynamic groups 1-8 days after breeding with monthly mixing events (8-10 sows removed and preplaced). Sows were housed in mixed parity groups in a free access stall system.
Static sows had a higher frequency of reciprocal aggression within the first 30 minutes of mixing while control sows had higher lesions 24 hours post-mixing. Throughout gestation, dynamic sows received more skin lesions and had a higher incidence of lameness. Dynamic mixing may serve as a viable alternative to group housing for pork producers provided that management strategies are refined to mitigate the effects of ongoing aggression.
Effects of gestation sow grouping practices on aggression and production (full article)
