The effects of cross-fostering on growth rate and post-weaning behavior of segregated early-weaned piglets

Cross-fostering involving piglets older than 2 d of age is often used in segregated early weaning (SEW) units to increase piglets' body weight homogeneity. This study was conducted to document the effects of such cross-fostering on weight gain, skin lesions, and post-weaning behavior of SEW piglets. Cross-fostering was done at 6 ± 1 d of age, in half of the 32 litters studied, by exchanging two piglets between pairs of litters. Piglets (n = 256) were weighed at birth, fostering, weaning (day 18 ± 1), and every week during the next month. The behavior of piglets was video-recorded during 3 h after weaning, and during 1 h on days 19, 20, 22, 24, 31, 38 and 45. Adopted piglets gained only 76% of the weight of non-adopted piglets between fostering and weaning (P < 0.001) and this difference persisted until day 45 (P < 0.05). Piglets from fostered litters fought less than control piglets during their first 2 d in nursery pens (P < 0.01) and skin lesions tended to be less frequent (P < 0.1). In all treatment gr...