Investigating the motivation to play in lambs.

@enThe aim of this study was to identify behaviours and ear postures linked to the appetitive, consummatory and post-consummatory motivational phases of play in male lambs, and to evaluate how cortisol was affected by play. Ten pairs of male lambs, Ovis aries were observed in a play arena three times a week for 4 weeks. They were kept in a holding pen for 5 min (appetitive phase) where they could look into the play arena (containing a ball, two chains and a tunnel) and thereafter released into the play arena for 20 min (consummatory phase). They returned to their home pen where they were observed for 6 min (post-consummatory phase). Direct observations were made in each location and behaviours were recorded as frequencies per min. Ear postures were recorded instantaneously every 15 s for 3 min per location. Saliva samples were taken in the 4th week for analysis of cortisol. Behaviours were analysed with a generalized linear model and cortisol with paired t-test. In the holding pen, the most common behaviours were walking, sniffing pen, standing facing play arena, standing facing alley, butting and pawing. Walking (P < 0.001) and standing facing play arena (P < 0.001) were higher during the 1st min whereas butting (P<0.001) was lower during the 1st min compared to the other 4 min. In the play arena, social play was more frequent than locomotor and object play (median: 1.85, 0.97, and 1.14 events per min, respectively). Total play and locomotor play decreased across the 20 min, whereas social play remained high until the 8th min. Total play (P<0.001) and social play (P<0.01) were most frequent during the 2nd week. Walking and standing were performed immediately after returning to the home pen but after the 1st min, lambs spent most of their time feeding. Raised and backward ear postures were common in the holding pen and play arena whereas plane ear postures were more common in the home pen. Salivary cortisol tended to increase after play (P=0.08). In conclusion, lambs showed different active behaviours together with raised and backward ear postures during the appetitive phase, high amounts of play together with backward and raised ear postures during the consummatory phase and mainly feeding together with plane ear postures during the post-consummatory phase. (C) 2014 Elsevier B.V. All rights reserved.