NEUROPHYSIOLOGICAL REGULATION OF TEMPERAMENT IN SHEEP

摘要

Selection of animals with amicable temperament can provide improvements in animal management, productivity, meat quality (Burrow 1997; Reverter et al. 2003) and, potentially, animal welfare. Temperament in ruminants is typically assessed using tests that measure escape and/or avoidance behaviour. Although such tests are practical, a better understanding of the neurophysiological mechanisms affecting temperament may increase our capacity to improve accuracy of selection with respect to temperament. Wehypothesised that 2 major neurotransmitters, γ -amino-butyric acid (GABA) and serotonin (5-HT), and their pathways, are responsible for temperament differences in livestock. These neurotransmitters are associated with anxiety in humans and animals (Haller 2001). Our objective was to investigate the role of GABA and 5-HT in the stress response of sheep using pharmacological agents that either increase (agonist) or decrease (antagonist) neurotransmitter action.