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 81 x 61.5 cm) that provided surrogate companionship. The behavioural and physiological responses of twelve mature horses during a 30-minute journey by trailer under the three treatments were compared.Behaviour (vocalisation, eating, head-tossing, pawing, and head turning) was 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<0.001), head turning (p<0.001), head-tossing (p<0.01) and pawing (p<0.01); eating behaviour increased (p<0.05). Physiological responses (increases in HR and T r and decreases in T p ) were also significantly reduced when travelling with a live companion (p<0.01). Travelling with the mirror did not significantly affect physiological responses compared with travelling alone, but the rise in 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<0.01), vocalising (p<0.05) and head tossing (p<0.05); eating behaviour increased (p<0.05). The only significant difference between travelling with a live 1 companion and a mirror was that the time spent turning the head round was less with a live companion (p<0.05). The provision of surrogate companionship in the form of a mirror was found to be preferable to travelling alone, but where possible a live companion is recommended. Isolation during transportation was found to suppress feeding behaviour. Although peripheral blood flow (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.

Scientific Opinion Concerning the Welfare of Animals during Transport

“…The surrogate companionship of the mirror also reduced increases in Tr and decreases in Tp compared with horses travelling alone. The only significant difference between travelling with a companion and a mirror was that time spent turning the head round was less with a companion (Kay and Hall, 2009). The provision of surrogate companionship was found to be preferable to travelling alone, suggesting that the mirror mimics visual contact (but not aural or odour contact) with conspecifics thereby minimising the sense of social isolation.…”

“…Isolation during transportation in a trailer was found to suppress feeding behaviour, and correlation analysis confirmed there was an inverse relationship between eating behaviour and other anxiety related behaviour. Kay and Hall (2009) recommended that horses are transported with a live companion, but if none are available, surrogate companionship, such as a mirror, is preferable to travelling alone.…”

Evolving protocols for research in equitation science

“…Why eye temperature? Decreases in body surface temperature in response to anxiety/fearprovoking situations have been recorded in a number of species, including humans (finger temperature, Ekman et al, 1983), sheep (ear-pinna temperature, Lowe et al, 2005) and horses (lower limb, Eddy et al, 2001; ear-pinna temperature, Kay and Hall, 2009). Circulatory changes in these areas undoubtedly reflect emotional state but, when measured using IRT, a number of factors relating to the surface being assessed will affect the readings.…”

Behavioural restriction.

“…Compared with socially housed conspecifics, isolation-housed rats show more asymmetrical body plans, indicating disrupted development (Sorenson et al, 2005), exaggerated corticosterone responses to stressors and impaired wound healing (Hermes et al, 2006), and shorter lifespans (Shaw and Gallagher, 1984;though cf. Skalicky et al, 2001); isolated horses show more stereotypic weaving (McAfee et al, 2002) and greater reactivity to acute stressors like trailer transport (Visser et al, 2008, Kay andHall, 2009); while isolated monkeys are, again, more stereotypic (Lutz and Novak, 2003), and have elevated heart rates, increased risks of atherosclerosis, and signs of immunosuppression (Watson et al, 1998;Lilly et al, 1999, Schapiro et al, 2000. Similarly, small, physically impoverished captive environments are also often detrimental compared with those that are larger and/or 'enriched' (more naturalistic or complex).…”