Comparative Aspects of Behavioural Activities of Beef Cows before and after Introducing a Stranger at Night

Abstract

Two groups of dry-lot feeding beef cows comprising 7 residents and a stranger (Groups A and B) were used to examine differences in social and maintenance behaviours before and after introducing the stranger at night, i.e. after dark when most resident animals were recumbent while resting or ruminating and there was less social activity. Agonistic and social licking interactions and incidents of eating, lying, standing and locomotion of each animal in each group were recorded during the daytime. Body weight change for each cow in the groups after introduction was also estimated. In Group A, there was little change in the frequencies of agonistic and social licking behaviours during the observation period. In Group B, there was more than a 2-fold increase in the frequency of agonistic behaviour following the introduction, though social licking changed little over the period. In each group, a relatively higher frequency of aggressive behaviour initiated and received by each stranger occurred on the 1st to 2nd day after introduction, which thereafter tended to decrease until the 7th day. The stranger in Group A significantly received more frequent aggression from residents than a stranger in Group B (P < 0.05). The strange cow in each group spent less time eating and more time in locomotion than residents. A significant negative correlation between eating time and relative body weight change in Group A (P < 0.05) suggested that a greater weight reduction in the strange cow after introduction is mainly associated with her less eating time.