Effect of space allowance during transport on the behavioural and physiological responses of lambs during and after transport

Abstract

AbstractThere is limited information on the behavioural and physiological responses of sheep to the components of road transport. Behavioural observations and physiological measurements of ‘stress’, injury and dehydration were made on weaned lambs (35 kg) before, during and after either stationary confinement or transport for 22 h at four space allowances (0·22, 0·27, 0·31 and 0·41 m2 per sheep). Two groups were not loaded (a control group with access to food and water, and a group with no food and no water for 12 h). During the confinement and transport period, the proportion of scans spent lying and the proportion of scans spent ruminating was significantly less than that before treatment (P < 0·01). After 3 h of transport, the proportion of scans spent lying was significantly less at the 0·22 m2 per sheep space allowance than at the other space allowances. The proportion of scans spent lying down was only significantly greater during confinement compared with transport at the 0·22 m2 per sheep space allowance and during the first 6 h at the 0·31 m2 per sheep space allowance. During transport, the heart rate and plasma cortisol concentration were greater than during stationary confinement (P < 0·05), indicating that some aspect of the journey was acting as a stressor. During transport the frequency of losses of balance and the frequency of slips was less at the 0·22 m2 per sheep space allowance than at the 0·27 and 0·41 m2 per sheep space allowances. However, there was no effect of space allowance on either plasma cortisol concentration or biochemical measures of injury. The median frequency of potentially traumatic events during transport was <5 per h and there was little evidence to suggest that increasing space allowance increased the risk of traumatic injury. During the first 12 h after treatment, the proportion of scans spent eating was greater and the proportion of scans spent lying were less than those spent before treatment (P < 0·001). Post-treatment, water intake and packed cell volume were greater in transported sheep than in control sheep (P < 0·05). However, there was no significant effect of 12 h without water on total plasma protein concentration and plasma vasopressin concentration (P > 0·05). Under the conditions of this study, sheep with a live weight of 35 kg can be transported for 12 h at space allowances of between 0·22 and 0·41 m2 per sheep without showing major physiological changes indicative of injury and dehydration. However, the sheep appeared to be hungry after 12 h without food and showed a cortisol and heart rate response to transport, indicating that some aspect of transport was acting as a stressor. A space allowance of 0·22 m2 per sheep cannot be recommended for 35 kg sheep as there is insufficient space for most of the sheep to lie down during transport. Whereas a space allowance of at least 0·27 m2 per sheep does allow most sheep sufficient space to lie down.