Farrowing conditions affect the reactions of piglets towards novel environment and social confrontation at weaning

At weaning piglets are confronted with a variety of challenges. In this study, we tested the effect of two rearing conditions on the behavioural responses of piglets towards social and non-social challenges at the time of weaning. A total of 81 piglets were reared either in an individual farrowing system with extra-space and straw (IF, n = 5 litters) or in a group farrowing system (GF, n = 5 litters). Two days before and 2-3 days after weaning piglets were subjected to a novel environment test and a social confrontation test for 10 min each. In the novel environment test IF-piglets spent significantly less time exploring objects in the test arena (P < 0.05), raised more often at the surrounding (P < 0.05), showed more jumping (P < 0.05), a higher number of entered squares (P < 0.05) and uttered more high-frequency calls (P < 0.001) compared to GF-piglets. These differences between IF- and GF-piglets were significant both 2 days before and 2-3 days after weaning. In the social encounter test the IF-piglets stayed longer near the unfamiliar piglets than GF-piglets (P < 0.05), showed less ambulation (P < 0.05), and tended to have longer naso-nasal contact (P = 0.073) and a longer latency until the first contact with the unfamiliar piglets (P = 0.079) compared to GF-piglets. The results suggest that the GF-piglets reacted less strongly towards both the novel environment and the unfamiliar piglets. It is concluded that piglets reared in an enriched group farrowing system are better adapted to non-social and social challenges at weaning compared to piglets reared in an enriched individual farrowing system. (C) 2002 Elsevier Science B.V. All rights reserved.