Epsilon Archive for Student Projects

Abstract

The aim of this study was to investigate if behaviour, ear positions and cortisol in lamb which were given access to play followed the different phases of the reward cycle of anticipation, consumption and relaxation. The study was done on 8 Dorset and 12 Dorset x Fine Wool uncastrated male lambs with an average age of 10 weeks. The lambs were housed pairwise in litter pens (2 x 3 m). Pairs of lambs were taken to a play arena (5.9 x 5.5 m) three times a week during five weeks (first week for learning). They were then first kept in a holding pen where they could look into the play arena for 5 minutes and thereafter released for 20 minutes in the play arena which had a ball, two chains and a tunnel. They walked back to their home pen and were observed for 6 minutes thereafter. Observations of behaviours were made as frequency per minute in all three places. Four different ear postures were recorded in the three places to study emotional valence in lambs. During the last week saliva sampling was done for cortisol analyses during the last week; one sample in the home pen before play and another in the home pen after play. Lambs showed significantly more anticipatory behaviour than non-anticipatory behaviour in the holding pen (p<0.01). Anticipatory behaviour did not change over the five minutes, and was higher during week 2-3 than week 1 and 4. In the play arena, play behaviour was significantly higher than other behaviours (p<0.01). Social play was higher than locomotor play and object play. Play behaviour was higher during the first ten minutes than the last ten minutes in the play arena (p<0.0001) and was highest during the second week of study (p<0.0001). The level of behaviours indicating relaxation was not higher than behaviours indicating no relaxation in the home pen after having been in the play arena (N.S.). Raised ear postures were most frequently recorded in the holding pen, whereas backward ear postures were more frequently recorded in the play arena and plane ear postures were most frequently recorded in the home pen both after play and on days without play. Saliva cortisol level increased after play in lambs during the first day, but not during the second and third day of sampling during the fourth week of play. It is concluded that lambs seem to show behaviours indicating anticipation to play and they do play in a known play arena, but relaxation after having played is less obvious during the first minutes. When given access to play the lambs seemed to pass through all three phases of the reward cycle expressing different anticipation, consumption and relaxation behaviours.