A forced lateralisation test for dairy cows and its relation to their behaviour

Abstract

Dairy cows’ emotional state can sometimes be inferred from their behaviour, for example previous studies have suggested that those passing a novel person to the right are more likely to be anxious than those passing to the left. We undertook two studies of cow behaviour as they passed a novel person, to validate these behaviours as emotional indicators, in addition to determining correlations to other indices of emotional state. Cows passing to the right were more likely to have a raised or tucked tail, sniff the ground, walk slowly and a faster exit when put in a crush, compared with those passing to the left, which had their ears held forwards. From a principal component analysis, it was determined that cows passing on the right side were also most likely to pass without turning their head towards the person, pass singly and defecate whilst passing. However, those passing to the left side were most likely to turn to look at the person and pass in pairs. Cows with high milk yields were more likely to pass on the right side. Measurements of side of passage were repeatable between experiments but those of ear position were not. It is concluded that side of passage past a person correlates with other behavioural indicators of the cow’s emotional state, with those passing to the right (i.e. left eye/right brain hemisphere) apparently more anxious. Evidence was also provided that high yielding cows are more anxious, as assessed by right side passage. With further validation, side of passage past a person could be developed as a simple measure of emotional state in dairy cows that can be conducted under field conditions.