Effects of handling and transportation on the heart rate and behaviour of sheep

Abstract

The effects of management procedures on the behaviour and heart rate of frequently handled sheep are described. The procedures investigated include spatial isolation, consisting of 4 m minimum separation from the rest of the flock imposed by flexi-netting; visual isolation, imposed by temporary fencing which confined the animal out of sight but within hearing of the rest of the flock; confinement with companions in a stationary trailer; transportation in a trailer with companions; introduction to a new flock. The total increases in heart rate (in beats min −1) were spatial isolation, 0; visual isolation, 28; stationary trailer, 0; transportation, 12; introduction to a new flock, 49 in the first 30 min reducing to 22 in the next 90 min. However, some of the changes were associated with changes of behaviour, but these could be allowed for to give “non-motor” heart rate increases, as follows; spatial isolation, 0; visual isolation, 20; stationary trailer, 0; transportation, 14; introduction to a new flock, 30 in the first 30 min reducing to 14 in the next 90 min. We suggest that non-motor heart rate provides a better assessment of the stressfulness of these procedures than is obtained from behaviour alone. Two further experiments investigated the effects on sheep heart rate and behaviour of dog handling. The effect of driving a flock by a shepherd and dog was to raise sheep heart rate to 163 beats min −1 which probably represents the maximum sustainable heart rate for this breed of sheep, with instanta-neous values of 262 beats min −1 being achieved, 3.5 times the pre-trial level (80 beats min −1). Heart rate recovered slowly and was still elevated 2 h after the experiment. The effect of approaching a flock of 5 sheep was to produce a series of transient increases, averaging 79 beats min −1 for approach by man with dog and 45 beats min −1 for man alone. These increases occurred in the absence of active behaviours but were of short duration (median 27 s). It is concluded that heart rate and behaviour together provide a good indication of an animal's reactions, although further information on the correlations with other stress indicators is needed.