Can tail-in-mouth behaviour in weaned piglets be predicted by behaviour and performance? By Camilla Munsterhjelm, Mari Heinonen, Anna Valros. In: Appl. Anim. Behav. Sci.
This study aimed to identify characteristics of pigs performing tail-in-mouth behaviour (TIM; P, n =34), their recipients (R, n =23) and neutral penmates (N, n =31) at two occasions, the first being at weaning (4 weeks of age) before TIM was observed in the pen and the second being at 9 weeks of age when TIM had emerged, but no clinical tail lesions were observed. The groups (n =22) were formed by siblings, two gilts and two castrates. Behaviour was analysed as 24-hour time budgets and continuously sampled during 30minutes of the active part of the day. Category (P, R, N) effects were analysed at individual and (directed) dyad level. P was born significantly smaller than R, but the difference had disappeared at 4 weeks. Growth or sex distribution did not differ between categories. Category differences in performed behaviour were evident at 4 weeks of age, when P showed more overall activity and environmental exploration as compared to R, as well as more bouts of tail-nosing than N. Different aspects of behaviour changed in the different categories between 4 and 9 weeks of age. In P social activity increased significantly and went from no preference at 4 weeks to a significant preference for social actions for R over N at 9 weeks. N was socially passive at 9 weeks while receiving more social behaviour than the other categories. These differences in behaviour suggest that the categories represented different phenotypes of pigs.