Husbandry influences on some physiological parameters of emotional responses in calves

Abstract

Experiments with Jersey calves were designed to monitor changes in heart rate (H.R.) and plasma levels of corticosteroids resulting from experiences encountered under modern routine husbandry practices. Simple restraint and immobilization for venipuncture caused an elevation in H.R. from a resting rate of below 100 beats per minute (b.p.m.) to a rate in excess of 140 b.p.m. A 10 min restraint period induced the maximum increase in plasma corticosteroid concentration, from a resting level of 7.7 ng/ml to 28.8 ng/ml. Drastic reduction in living space for a 14 day period caused only a transient elevation in H.R. and plasma corticosteroid concentration in the period immediately after entering the cubicle. Transportation effects on H.R. and plasma corticosteroids were greater when the calves were transported free than when the same journey was repeated with the calf carried within a wooden cubicle. Recumbency during transportation resulted in a significant lowering of H.R. It is concluded that the wide range of stimuli encountered by calves under normal husbandry practices are capable of inducing varying degrees of emotional responses. These responses seemed to depend largely on the magnitude and degree of novelty inherent in the presented stimulus.