The use of a mirror reduces isolation stress in horses being transported by trailer

Abstract Horse trailers are a common form of transportation for horses and ponies and often require the animal to travel alone or with a single companion. The current study investigated the effect of transporting horses alone, in company or with an acrylic safety mirror (measuring 81cm×61.5cm) that provided surrogate companionship. The behavioural and physiological responses of 12 mature horses during a 30-min journey by trailer under the three treatments were compared. Behaviours (vocalisation, eating, head-tossing, pawing, and head-turning) were recorded. In order to assess circulatory changes that occur as part of the response to transport, heart rate (HR), rectal ( T r ) and ear-pinna ( T p ) temperatures were recorded. When travelling with a live companion significantly less time was spent vocalising ( p p p p p T r and decreases in T p ) were also significantly reduced when travelling with a live companion ( p T r and fall in T p was reduced ( p =0.052 and p =0.051, respectively) and can be considered a trend. When travelling with a mirror significantly less time was spent turning the head ( p p p p p T p ) has been used to assess transport stress in other species it has not previously been used in the horse. Further evaluation of this non-invasive measure is now required.