The Effects of Rearing in Individual Crates on Subsequent Social-Behavior of Veal Calves
Résumé
The aim of this study was to determine the effects of rearing in individual crates on the subsequent social behaviour of calves. The calves (n = 32) were divided into groups of eight animals reared in crates until 19 weeks of age, eight reared in crates until 14 weeks of age and grouped together thereafter and 16 reared always in groups, which were re-allotted at 14 weeks of age. The social encounters were recorded on the days the calves were grouped at 14 weeks (intra-treatment mixing) and at 19 weeks, when created calves were mixed with those that had always been in groups (inter-treatment mixing). The social behaviour was then observed 1, 5 and 12 days thereafter. The data were analysed with Kruskal-Wallis and Mann-Whitney tests. After mixing at 14 weeks, more agonistic encounters and fewer non-agonistic encounters were observed in groups of previously crated calves than in groups of calves that had always been in groups (butts per calf per 2 h period, 6.6 vs. 1.8, P \textless 0.01; licks per calf per 2 h period, 3.9 vs. 7.5, P \textless 0.05). After mixing at 19 weeks, there were only slight differences between calves. The calves that had always been in groups achieved hierarchical ranks higher than crated calves in 14 out of 16 occurrences with calves crated until 19 weeks of age but in only 5 out of 16 occurrences with those crated until 14 weeks of age. It is concluded that the reduction of social contacts has short-term effects on the social behaviour of calves and that these effects can be reversed by mixing calves with similar social experience.