Abstract: Reasons for performing study: Little information exists on the immunological effects of transport or the use of supplements to minimise transport stress. Objectives: To establish baseline ranges and evaluate immunophenotypic and functional changes associated with transport and a nutritional ‘adaptogen’ supplement. Methods: Horses received either supplement (n = 10) or placebos (n = 9) during the 30 day study. After 28 days in stalls, 12 horses (6 supplement; 6 placebo) were transported for 24 h, then unloaded and recovered. Venous blood samples were collected on Days 1, 14 and 28 to establish baselines, and on Days 28, 29 and 30 to examine changes during transport and recovery. Results: Transport prompted elevations (P<0.05) in cortisol concentration, neutrophil count and white blood cell counts, while lymphocyte subpopulation counts (CD3+, CD4+, CD8+, CD21+) decreased (P<0.05). Normal phenotypic lymphocyte profiles returned within 24 h of recovery. Supplement effects on immunophenotype (CD21+ and CD8+) were observed in stabled horses (P<0.05), but not in transported horses. Conclusions: These results provide insights into the immunological mechanisms associated with long-term transport. Potential relevance: The existence of a small window of immunological uncertainty follows long-term transportation, enhancing the potential risk of infectious disease in susceptible individuals.

Abstract: Abstract Analysis of salivary cortisol is increasingly used to assess stress responses in horses. Since spontaneous or experimentally induced increases in cortisol concentrations are often relatively small for stress studies proper controls are needed. This requires an understanding of factors affecting salivary cortisol over longer times. In this study, we have analysed salivary cortisol concentration over 6 mo in horses (n = 94) differing in age, sex, reproductive state and housing. Salivary cortisol followed a diurnal rhythm with highest concentrations in the morning and a decrease throughout the day (P < 0.001). This rhythm was disrupted in individual groups on individual days; however, alterations remained within the range of diurnal changes. Comparison between months showed highest cortisol concentrations in December (P < 0.001). Cortisol concentrations increased in breeding stallions during the breeding season (P < 0.001). No differences in salivary cortisol concentrations between non-pregnant mares with and without a corpus luteum existed. In stallions, mean daily salivary cortisol and plasma testosterone concentration were weakly correlated (r = 0.251, P < 0.01). No differences in salivary cortisol between female and male young horses and no consistent differences between horses of different age existed. Group housing and individual stabling did not affect salivary cortisol. In conclusion, salivary cortisol concentrations in horses follow a diurnal rhythm and are increased in active breeding sires. Time of the day and reproductive state of the horses are thus important for experiments that include analysis of cortisol in saliva.

Abstract: The benefits to humans of equine-assisted therapy (EAT) have been well-researched, however few studies have analyzed the effects on the horse. Understanding how differing mental states of humans affect the behaviour and response of the horse can assist in providing optimal outcomes for both horse and human. Four humans clinically diagnosed and under care of a psychotherapist for Post-Traumatic Stress Disorder (PTSD) were matched physically to four neurotypical control humans and individually subjected to each of 17 therapy horses loose in a round pen. A professional acting coach instructed the control humans in replicating the physical movements of their paired PTSD individual. Both horses and humans were equipped with a heart rate (HR) monitor recording HR every 5secs. Saliva samples were collected from each horse 30 min before and 30 min after each trial to analyze cortisol concentrations. Each trial consisted of 5 min of baseline observation of the horse alone in the round pen after which the human entered the round pen for 2 min, followed by an additional 5 min of the horse alone. Behavioural observations indicative of stress in the horse (gait, head height, ear orientation, body orientation, distance from the human, latency of approach to the human, vocalizations, and chewing) were retrospectively collected from video recordings of each trial and analyzed using a repeated measures GLIMMIX with Tukey's multiple comparisons for differences between treatments and time periods. Horses moved slower (p < 0.0001), carried their head lower (p < 0.0001), vocalized less (p < 0.0001), and chewed less (p < 0.0001) when any human was present with them in the round pen. Horse HR increased in the presence of the PTSD humans, even after the PTSD human left the pen (p < 0.0001). Since two of the PTSD/control human pairs were experienced with horses and two were not, a post-hoc analysis showed that horses approached quicker (p < 0.016) and stood closer (p < 0.0082) to humans who were experienced with horses. Horse HR was lower when with inexperienced humans (p < 0.0001) whereas inexperienced human HR was higher (p < 0.0001). Horse salivary cortisol did not differ between exposure to PTSD and control humans (p > 0.32). Overall, behavioural and physiological responses of horses to humans are more pronounced based on human experience with horses than whether the human is diagnosed with a mental disorder. This may be a reflection of a directness of movement associated with humans who are experienced with horses that makes the horse more attentive. It appears that horses respond more to physical cues from the human rather than emotional cues. This knowledge is important in tailoring therapy programs and justifying horse responses when interacting with a patient in a therapy setting.

Abstract: A behavioral assessment of horses who were being used and not used in therapeutic riding programs was conducted to help determine useful methods of selecting horses for use in therapeutic riding programs. A total of 103 horses (76 horses from five therapeutic riding centers and 27 non-therapeutic riding horses from four sites) were used. Temperament survey for each horse were completed by three riding instructors at each therapeutic riding center or by the individual most knowledgeable about the horse at the other sites. Twenty personality traits from the survey were used to quantify temperament. Concentrations of plasma cortisol, norepinephrine and epinephrine were also measured in each horse. A reactivity test was then conducted which involved introducing three novel stimuli: a walking and vocalizing toy pig placed on a cardboard surface in front of the horse for 20 s; popping a balloon near the horse's flank area; and suddenly opening an umbrella and holding it open in front of the horse for 20 s. Reactions (expressions, vocalizations and movement) to each of the stimuli were scored and used to calculate an average reactivity score for each horse. The therapeutic riding instructors did not often agree on the temperament of their center's horses. The personality trait ratings made by the therapeutic riding instructors at each center were on average significantly correlated (P<0.01, r>0.52) for only 37.8% of the horses for any two instructors and 7.8% for three instructors. No significant correlations were found between temperament, reactivity, and the hormone concentrations (r<0.19), but regression analysis indicated a possibility of predicting temperament from the reactivity score and hormone concentrations (P<0.08). There was also a tendency for relationships between extremes in temperament (desirable vs. undesirable) and the hormone concentrations (P<0.09), and between extremes in reactivity (low vs. high) and the hormone concentrations (P=0.08). The difference in ratings among riding instructors indicates a need for more collaboration between instructors when evaluating horse temperament. This study also indicates that it was very difficult to objectively determine the suitability of horses for therapeutic riding programs regarding their temperament and reactivity, probably because other traits (e.g., smoothness of gait) are also considered very important.

Abstract: Abstract Stress is a generic concept describing the body's reaction to external stimuli, including both physiological and psychological factors. Therefore, by definition, the assessment of psychological stress in the exercising horse encompasses the problem of teasing apart the psychological and physiological factors both of which result in stress responses. The present study reviews the existing literature on various measures of stress taken specifically in the context of equitation science. Particular attention has been paid to short-term effects, and commonly used measurements of short-term stress include heart rate, a number of heart rate variability parameters, blood or saliva cortisol levels, eye temperature, and various behaviour parameters including in particular behaviour patterns presumably indicative of conflict with the rider's/trainer's aids. Inspection of the individual studies' results revealed that disagreement between these different measures of stress is commonplace. For physiological parameters, the largest proportion of agreement (i.e. both parameters simultaneously indicated either higher, insignificant or lower stress compared to a control treatment) was found for heart rate and heart rate variability parameters, while generally limited agreement was found for cortisol. It appears that cortisol levels may not be particularly useful for assessing/assessment of the valence of a situation in the exercising horse as cortisol levels are predominantly linked to activation and exercise levels. Although heart rate variability parameters reflect in theory more closely sympathovagal balance compared to cortisol levels, great care has to be taken regarding the use of appropriate time-frames, appropriate raw data correction methods as well as the use of appropriate equipment. In spite of its wide-spread and apparently successful use, popular equipment may in fact not be accurate enough under field conditions. Eye temperature is another promising parameter for assessment of psychological stress, but the technique is likewise susceptible to application errors. Given the high susceptibility of physiological parameters to errors at various experimental stages, behavioural rather than physiological parameters may in fact provide more accurate measures of valence when conducting experiments in the exercising horse. Behavioural parameters that appear to be particularly practical in assessing stress in ridden horses' behaviour are associated with frequencies of behaviour indicative of conflict. However, while increased frequencies of are a good indicator of stress, the absence of conflict behaviour does not provide proof of the absence of stress due to the possible occurrence of conditions such as Learned Helplessness. In future studies, the above issues should be taken into consideration when designing experiments to assess psychological stress in ridden horses.