Group gestation housing with individual feeding-I: How feeding regime, resource allocation, and genetic factors affect sow welfare

As group gestation housing replaces the use of sow stalls, research consensus on how to best manage welfare challenges associated with group systems is needed and valued by industry and policymakers. At present, there is a lack of welfare research directly comparing different group sow housing systems which incorporate individual feeding methods. The aim of this review was to assess current research findings and highlight further areas of research required to provide producers with information about which individual feeding methods best promote sow welfare and productivity in group systems. Regardless of feeder type, feed restriction during gestation is associated with hunger-motivated stereotypic activity, increased aggression, and feeding competition within group sow housing. Further, some systems, such as ESFs which provide sows with a high degree of protection while eating, present unique challenges by requiring sows to eat sequentially rather than simultaneously as a group. Bulking diets with fibre effectively alleviates many hunger-motivated behaviour and welfare concerns. However, dietary fibre also increases feeding time which can cause crowding of sequential feeding systems, thereby reducing feeder capacity. Artificial selection against aggression and aberrant behaviours and the tailoring of genotypes to specific feeding systems as a means of increasing sow welfare is largely unstudied in the scientific literature and presents a valuable area for future sow research.