The effects of food level on general activity and aggression in dynamic groups of 30 sows

Abstract

Aggression in group housed sows is often related to competition over food. Sequential feeding avoids the confrontations at the trough, but puts them at the feeder entrance. Studies of large groups of dry sows using computerised feeding systems showed that vulva biting was most frequent after visits when only a small amount of food had been dispensed (Buré, 1991). This suggests that frustrated feeding motivation may cause increased aggression. A Swedish survey into group housed sows found a link between sow condition and mean injury scores: farms averaging a high injury score had a larger proportion of thin sows (Svendsen et al., 1990). The present study aimed to investigate the hypothesis that in large dynamic groups of sows a high food level results in lower levels of aggression and associated skin lesions.