Thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road

Abstract

The study was conducted to evaluate the thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road. A total of 44 Chamarita breed adult ewes were randomly allotted to one of two groups, one control group (untransported) and transported group (journey of 4 h), and blood stress indicators were measured 1 day before transport and at four time points post-transport (0, 4 and 24 h). Thermophysiological profiles of ewes were measured by temperature buttons (iButton Thermochron^® ) and placed in intravaginal sponges. Direct observations, with a combination of scan and behaviour sampling, were carried out to collect information on individual behaviour and the time it took the ewes to drink water, eat and rest after returning to their pen respectively. Transported ewes lost approximately 1 kg live weight compared to controls and had higher body temperatures until 12 h post-transport. Cortisol, glucose, non-esterified fatty acid (NEFA) concentrations as well as the neutrophil-lymphocyte ratio (N/L) and other physiological indicators were higher immediately after unloading in transported ewes but mostly returned to normal after 4 h, with complete recovery after 24 h. Behavioural analysis post-transport demonstrated that transported ewes chose to eat before drinking and spent less time resting than controls in the first 3 h after unloading. The study demonstrates that transportation even under short-journey conditions induced behavioural, physiological and thermophysiological responses indicative of the induction of significant stress, leading to live weight shrinkage that may jeopardize farmer's incomes. Finally, results of this study validated the use of iButton Thermochron^® data loggers for monitoring the stress response during transport.

Keywords: iButton Thermochron®; sheep; stress hyperthermia; transport.