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

Abstract

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 groups, eating frequency was low on days 18 and 19 and increased abruptly on day 20. In conclusion, fostering impaired growth of piglets, but also facilitated their adaptation to unacquainted piglets after weaning.