Behavioural Effects of Social Mixing at Different Stocking Densities in Prepubertal Lambs
The behavioural effects of mixing individuals from two different flocks were studied in prepubertal lambs of about 20kg body weight kept at either low (1 animal m−2) or high (3.3 animals m−2) stocking densities. At both densities, flock mates associated
preferentially with one another over the three experimental days. The social mixing conditions decreased the total number of aggressive interactions (including head-to-head clashes, head-to-body buttings and mountings). Since animals associated preferentially with flock mates, aggressive behaviours
were also preferentially directed towards individuals from the same flock. Males initiated significantly more aggressive interactions than females. The total number of aggressive interactions received was similar for males and females, but females received more mountings than males. Stocking
density, therefore, had no effect on aggressive behaviour. These results are discussed as they relate to transport and it is suggested that social mixing may not be a welfare problem in prepubertal lambs.