Vocal behaviour in cattle: the animal's commentary on its biological processes and welfare

The vocalizations of cattle provide conspecifics with meaningful informatio n about the caller. If we can learn how to interpret this information corre ctly, it could be used to improve management and welfare assessment. Vocali zation may be viewed as a subjective commentary, by an individual, on its o wn internal state. The vocal behaviour of cattle is potentially a useful in dicator of their physiological and psychological functioning. In the first part of this article we ask what information is exchanged usin g auditory cues. Vocalizations provide information on the age, sex, dominan ce status and reproductive status of the caller. Calves can recognize their mothers using vocal cues but it is not clear whether cows recognize their offspring in this way. Vocal behaviour may play a role in estrus advertisem ent and competitive display by bulls. Under experimental conditions involvi ng pain or social isolation, vocal response is useful as an indicator of we lfare, if properly used. Unlike commonly used physiological measures, it ca n be recorded non-invasively and varies on a number of quantitative and qua litative dimensions. In the second part we review methodological approaches to the study of voca l behaviour and their application in cattle welfare research. Methods may f ocus on the actions of the vocalizing animal and the conditions which elici t vocal behaviour, the response of an animal to hearing another's vocalizat ions, or interactions between sender and receiver. We argue that vocal behaviour in cattle may be valuable in welfare studies if the endogenous, exogenous and developmental factors influencing its expr ession can be more thoroughly investigated and understood. (C) 2000 Elsevie r Science B.V. All rights reserved.