Management of predelivery stress in live export steers

Summary

There is increasing recognition of the need to minimize stress in farm animals both as a result of public concern for the welfare of animals and from the ongoing need to increase the efficiency of animal production. Improved welfare practices that minimize stress during handling and transportation prior to the sea voyage may have a significant effect on the mortality and morbidity of livestock. This literature review examines the impact of transport and handling in the pre-delivery phase of the export process on cattle. It addresses two stress theories that support a current descriptive definition of stress. The physiology of the neuroendocrine systems are discussed in relation to stimulation by external stressors.

In addressing the hypothesis that stress induces dehydration, body fluid compartments and their measurement are discussed along with the physiological regulation of body fluids and fluid osmolarity. The physiological significance of neuroendocrine stimulation on water and electrolyte balance and the use of electrolyte and fluid therapy on relieving transport stress are discussed. There is anecdotal evidence in cattle to suggest that dehydration impacts upon the body's metabolism. This may result in a catabolic state that leads to a reduction in body mass. The effects of stress on metabolism and the gastrointestinal tract are discussed with respect to stressor effects on live weight and body composition. The associated effects of rest and recovery periods, injuries and mortalities associated with transport and sexual differences in the coping ability of cattle to transport stress are mentioned.