Individual differences in behaviour and in adrenocortical activity in beef-suckler cows.

@enThe aims of this study were to investigate the existence of individual behavioural strategies in beef-suckler cows in a stable herd, whether these strategies are related to basic activities and to adrenocortical activity, and whether they are consistent in a situation of social competition. Social interactions of 19 beef-suckler cows were recorded over a period of 3 months for 208 It. The animals were classified into three groups of different social strategies by factor and cluster analysis: agonistic dominant (AD), nonagonistic (NA) and agonistic challenging (AC). Basic activities (lying, standing, feeding, walking) and the concentration of faecal cortisol metabolites were compared between groups. Consistency of social strategies was tested in a situation characterised by increased social competition (reduced number of feeding places). In the undisturbed social situation, AD-animals initiated most agonistic interactions, whereas AC-animals received most and showed least social licking. NA-animals initiated less agonistic interactions and performed more social licking than AC-animals and most head play. The dominance values were highest in AD-animals, but did not differ between NA- and AC-animals. AC-animals had the highest frequency of walking, standing, feeding and drinking, and they kept lying shortest. Concentrations of faecal cortisol metabolites were higher in NA-animals than in AC. Identified social strategies were confirmed in a social competition test. Our results revealed that the cows showed different behavioural social strategies consistent across situations of low and high social competition. The three strategies differed in social behaviour, basic activities and adrenocortical activity. Thus, NA- and AC-animals seemed to adopt two different strategies to cope with a subdominant status. (C) 2003 Elsevier B.V. All rights reserved.