The use of a ‘go/go’ cognitive bias task and response to a novel object to assess the effect of housing enrichment in sheep (Ovis aries)

It is widely acknowledged that environmental enrichment can improve animals’ welfare and emotional state. This study used cognitive bias and response to a novel object to assess the effect of enriched housing on emotional state in sheep. Eighteen sheep were trained to discriminate between high-quality and low-quality reward locations using a go/go task. Sheep were allocated to a housing treatment (enriched or standard) for three weeks. Judgement bias tests were conducted using three ambiguous, unrewarded locations across three days, followed by assessing responses to a novel object. Effects of anxiety levels shown in training on responses to ambiguous locations and to the presence of a novel object were assessed. Enriched-housed sheep tended to have shorter latencies to approach ambiguous positions than standard-housed sheep (P=0.08), particularly to the near and middle locations. Sheep from standard housing tended to have shorter latencies to approach food with the novel object present than sheep from enriched hosing (P=0.06). This study shows that enrichment can affect emotional state and that go/go tasks can be successful in sheep and should be considered in future studies of emotional state.