A note on reaction to novel stimulus and restraint by therapeutic riding horses

Abstract

Little research has been done to measure reactivity objectively in therapeutic riding horses (TRH). As individual reactivity and chronic stress could be assessed by exposing animals to acute, novel stressors, the authors of this work aimed at comparing reactions of TRHs and jumping horses (JH) to two challenges. Four TRHs and four JHs were exposed to a restraint covering their head with a hood for 1 h and to a startling stimulus (a 40 cm long, red and white synthetic holiday garland shaken with a rustling noise inside the box). Heart rate (HR) and heart rate variability (HRV) were recorded continuously and telemetrically, the reaction was video-recorded and analysed with a software for behavioural analysis. Blood samples were collected before and after each challenge to determine lymphocyte proliferation and other biochemical parameters. Horses spent most of the time immobile, during the challenges (p < 0.05). TRHs had a significantly higher average basal HR than JH (p < 0.05), probably due to their better condition. HR varied among different behaviours during the restraint (p < 0.05): the average HR during “pawing” was higher than during other behaviours (p < 0.005). A significant decrease in the proliferation of lymphocytes in samples taken after the removal of the hood (p < 0.05) was found, while the other stress related parameters did not vary significantly after the challenges. The authors conclude that TRHs did not react less than JHs to the new stimuli and this should be taken into consideration while planning their daily work and management.

Introduction

Therapeutic riding (TR) is an animal-assisted therapy supporting or reinforcing motor, biochemical and mental functions in disabled people by means of horse-riding (De Lubersac and Lallery, 1977). Physical and behavioural characteristics, health conditions and management patterns associated with the horses being used in such therapy are critical to the programme's quality as well as its success. In terms of reactivity, a therapeutic riding horse (TRH) should not be excessively reactive. Nor should it be excessively reactive to new stimuli or prone to sudden movements (Engel, 1992). Any reactivity variation in horses to behavioural tests may indicate the existence of stressful situations (Visser et al., 2001). If neglected, they might turn out to be a potential cause of problems for the horse's well-being as well as for the patients safety. So far, few studies have been published aiming at measuring TRHs’ behaviour and reactivity objectively as well as assessing whether these features might be used as selection criteria (Anderson et al., 1999). Furthermore, few researches have been carried out in order to emphasise whether the work performed by TRHs might negatively impact their well-being and, as a consequence, therapy quality. Since limited specific information is available concerning THRs, this article aims at assessing reactivity in some THRs. To that end, the horses were exposed to two challenges and their behavioural and physiological responses were compared to jumping horses’ (JH) reactions.