Abstract

Problems exist in welfare quantification of stressors due to variation in animal responses. A theory, based on adaptation to repeated exposure of a stressor, is proposed for objective assessment of welfare. Cattle of three ages were exposed repeatedly to transport, or aspects of transport. Cattle aged 6 weeks showed a declining tachycardic response to repeated transport (p<0.05). Cattle aged 3-6 months showed no consistent pattern of heart rate response to transport, although bradycardia was observed in some animals. Bradycardia was also observed in 2 year old bulls, the incidence of which declined with repeat exposure to trailer loading. Heart rate decreased over transport in bulls unfamiliar with trailer loading (p<0.05), while no change in heart rate was seen in bulls familiar with a trailer.

LH, Jacobson, and CJ Cook

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 103-106, 1996