Social stress from mixing sows has the potential to negatively affect sow production and welfare. Housing sows in stalls from weaning until five weeks after breeding is a common strategy used to prevent aggression and ensure control over individual feeding during breeding, conception and implantation. However, alternative management options are needed as pressure to reduce stall use is likely to continue. This study compared the effects of three mixing strategies on sow performance in group sow housing. Treatments included: Early mixing (EM) – sows mixed directly at weaning; Pre-socialisation (PS) – sows mixed for two days at weaning, then stall housed for breeding and until five weeks gestation, then remixed; and Late mixing (LM) – sows stall-housed at weaning and mixed into
groups at five weeks gestation. The results show no differences in the aggressive behaviour among treatments. Analysis of production showed a lower conception rate in LM groups than in EM and PS groups P<0.05. There were no differences in total born, piglets born alive or mummies among treatments, but a there were significantly fewer stillborn piglets in the EM treatment. Fewer stillborn piglets may have resulted from improved fitness and/or activity levels during early gestation. Overall, sows performed similarly in all treatments indicating that, under good management conditions, mixing sows at weaning does not impact sow performance or welfare.
