Sheep exhibit a positive judgement bias and stress-induced hyperthermia following shearing

Abstract

The detection of judgement biases may improve welfare evaluations by measuring the cognitive component, particularly the valence, of affective states. Judgement biases have been successfully demonstrated in various laboratory animals but only recently in sheep. Chronic stressors have been found to induce a negative judgement bias and a short-term stressor (restraint and isolation stress) a positive judgement bias. Here we examine the impact of the short-term stress of shearing on judgement bias, haematology, plasma cortisol and stress-induced hyperthermia (SIH) in sheep. Twenty-four Merino ewes were trained to spatially differentiate between positive and negative reinforced bucket locations ..