Arena behaviour is a possible selection criterion for lamb-rearing ability; it can be measured in young rams and ewes

In order to further assess the usefulness of behaviour as a possible selection criterion for the improvement of lamb-rearing ability, the arena behaviour of rams and ewes of a flock selected for rearing ability (Fertility Flock) was compared to that of rams and ewes of an unselected flock (Random Flock). Arena behaviour was measured in an approach/avoidance test wherein animals were placed alone in a narrow arena for 10 min. During this period, their attraction to a group of sheep in a pen at one end of the arena relative to their avoidance of a human being sitting in the arena in front of this pen was assessed by quantifying five behaviours; minimum, mean and maximum distance from the human, total distance moved in the arena and number of bleats. These behavioural measurements were made at 6, 12 and 20 months of age. Of the five behaviours measured, total distance travelled consistently differed between the two flocks, Fertility Flock animals travelling, on average, only 60% as far as the Random Flock animals. Number of bleats also differed between the two flocks, but only at 6 and 12 months of age. Importantly, these differences appeared in both ewes and rams. The study also showed that these behaviours were all moderately to highly repeatable. These results further support the possible usefulness of arena behaviour as a means of genetically improving the lamb-rearing ability of ewes and indicate that rapid genetic progress may be possible since these behaviours can be measured early in the life of animals and in animals of both sexes.