Behavioral and cortisol responses of shelter dogs to a cognitive bias test after olfactory enrichment with essential oils

Abstract

A shelter environment tends to present different types of stressors dogs need to cope with. Recent work has shown that olfactory enrichment with essential oils might be able to modify the affective states of certain species (dogs, cats, horses, zoo animals…). In these studies, the welfare measurements included physiological indicators, such as corticosteroid levels,and/or behaviors related to chronic stress. The olfactory effects of 9 essential oils ( Cananga odorata,Cistus ladaniferus, Citrus aurantium, Cupressus sempervirens, Juniperus communis var. montana, Lavandula angustifolia, Laurus nobilis, Litsea citrata, Pelargonium graveolens ) and a blend of these oils were explored on a cognitive bias test, cortisol levels and the behaviors of 110 shelter dogs (n= 10 dogs within each group). Olfactory enrichment with the blend resulted in a reduced latency to the ambiguous cue, indicating a more optimistic bias and improved welfare. The results of this study suggest that olfactory enrichment with essential oils can have specific effects on the affective states and behaviors of shelter dogs, and could therefore be useful for shelter management. In addition, as not all of the essential oils tested individually were effective, more research should be conducted to better understand the effects of each individual essential oils on dogs. Keywords: behavior; cognitive bias; cortisol; dogs; essential oils; olfactory enrichment; shelter; welfare.