Lateralization of behavior in dairy cows in response to conspecifics and novel persons

Abstract

The right brain hemisphere, connected to the left eye, co-ordinates fight and flight behaviours in a wide variety of vertebrate species. We investigated whether left eye vision predominates in dairy cows’ interactions with other cows and humans, and whether dominance status affected the extent of visual lateralisation. Although there was no overall lateralisation of eye use to view other cows during interactions, cows that were submissive in an interaction were more likely to use their left eye to view a dominant animal. Both subordinate and older cows were more likely to use their left eye to view other cattle during interactions. Cattle that predominantly used their left eye during aggressive interactions were more likely to use their left eye to view a person in unfamiliar clothing in the middle of a track by passing them on the right side. However, a person in familiar clothing was viewed predominately with the cows’ right eye when they passed mainly on the left side. Cows predominantly using their left eyes in cow to cow interactions showed more overt responses to restraint in a crush compared to cows who predominantly used their right eyes during interactions (crush scores: left eye users 7.9, right eye users 6.4, SED = 0.72, P = 0.01). Thus interactions between 2 cows and between cows and people were visually lateralised, with losing and subordinate cows being more likely to use their left eye to view winning and dominant cattle and unfamiliar humans.