Stall housing has received lots of criticism for being so restrictive. It has been demonstrated that sows in groups can perform as well as those in stalls, so gestation stalls are being banned in many countries. An area that needs to be studied is how mixing aggression may disrupt estrus in sows. Mixing sows at weaning (early mixing) compared to at 5 days gestation (late mixing) had no differences in aggression, lameness or cortisol levels. When mixed for two days after weaning, stall housed for breeding, then mixed back (pre-socialization), skin injuries were lower on the first mixing but higher on the second. Overall injuries were low and the mixing treatments did not affect welfare. Estrus behaviour in early mixing groups occurred at an increased frequency from 30% to 48% in days 3 to 4 and they had the highest conception rate with a significant reduction of stillborn piglets. This may be due to the allowance of movement in early pregnancy. Lowest conception was found in the late mixing group. The correct timing of stress post-weaning can bring on estrus.
Managing Sows in Groups from Weaning – Are There Advantages (full article)
