Abstract: The interaction of horses with humans is a dynamic state, but it is not clearly understood how horses perceive humans. Nervousness is transmissible from humans to horses indicated by increased horse heart rate (HR), however no studies have investigated whether horses can differentiate between humans who are physiologicallystressed (eg. after exercising) as opposed to psychologically-stressed (eg. feeling nervous/afraid). Horses (N=10) were randomly subjected to each of four treatments: 1) no human [control], 2) a calm human comfortable around horses [CALM; N=2 humans], 3) a physically-stressed human [PHYS; human exercised to reach 70% of maximum HR; N=2 humans], and 4) a psychologically-stressed human [PSYCH; human who was nervous around horses; N=14 humans]. Humans ranked themselves on a scale of 1-10 for their nervousness around horses. Both humans and horses were equipped with a HR monitor. Behavioural observations of the horses [gait, head position relative to the withers, distance from human, orientation toward human] were recorded live. Horses were allowed to wander loose in a round pen for 5 minutes of baseline recordings, at which time the human subject entered the round pen, stood in the centre and placed a blindfold over his/her eyes. The human remained in the centre of the round pen for an additional 5 minutes. Horse HR during control did not differ from when the human was present in the CALM and PSYCH treatment, and was lower during the PHYS treatment (51a vs 54a vs 55a vs 45b bpm for control, CALM, PSYCH and PHYS respectively; a,b differ p<0.0001). Over the 5 minute test period, horse HR decreased in PHYS and PSYCH (p<0.01) whereas it increased in CALM (p<0.0001). Horse HR decreased with increasing human rank of nervousness around horses (p=0.0156), and horses stood nearer to the human when they faced the human (p<0.0001) regardless of treatment. Horses moved at a faster gait in the control treatment, and their gait was slowest in the PSYCH treatment (p<0.0001), and the horse’s head position was lower in the PHYS and PSYCH treatments compared to CALM or baseline (p< 0.0001). A lower horse head position was positively correlated to a lower horse HR (p<0.0001) and negatively correlated to horse age (p<0.0001). Human HR was affected by treatment, with PHYS having the highest HR (p<0.0001). Human HR increased when the horse was facing away from the human, even though the human was blindfolded (p=0.0395). Overall, horses appear to be influenced by the physiological and psychological state of a human without any direct contact. Horses’ posture does reflect their physiological state. Understanding how horses react to human physiological and psychological states is especially important in equine-assisted activities, where the response of the horse has specific implications for the human participant.

Abstract: The heart rate and behaviour of 14 adult saddle horses, eight crib-biters and six normal controls, were investigated. Initially, the relationship between crib-biting and heart rate was investigated while the horses were undisturbed. The horses were tested when restrained with a lip twitch, and assessed when they were exposed suddenly to the rapid inflation of a balloon. The heart rate of the crib-biters during crib-biting was lower than during other behaviours. The crib-biters had a higher overall mean heart rate (P<0.05) suggesting that they may have had a higher basal sympathetic activity. After the application of the twitch, all the horses had a transient increase in heart rate which returned to basal values more rapidly in the crib-biters. The crib-biters were less reactive to the lip twitch, five of the six investigated remaining calm, and after the release of the twitch, they spent more time nibbling (P<0.05) than the control horses. The crib-biters reacted more strongly to the inflation of the balloon (three of the six reacted), and after it had been inflated they spent more time walking in the box.

Abstract: We carried out a questionnaire survey of the caretakers, using 86 riding horses kept in the Equestrian Park, Tokyo (Japan Racing Association). The questionnaire survey used a 5-point scale and a 3-point scale to assess several caretakers' impressions of each horse's temperament, on the basis of the norm and the horse's tendencies in ordinary care and daily training. Factor analysis of the temperament scores obtained with the 5-point scale questionnaire revealed three mutually independent factors that we named “anxiety”, “novelty seeking” and “understanding”. In order to verify the reliability of this questionnaire survey, a balloon reactivity test was conducted using the same horses. Each horse was introduced into an unfamiliar indoor arena (7 mx12.5 mx3 m) in the center of which two balloons slowly revolved. The horses' responses were assessed by recording changes in their behavior and heart rate (HR) during the 5 min experimental period. By comparing the questionnaire survey and the balloon reactivity test, it was found that the horses evaluated as highly anxious by the caretakers tended to show greater HR increases and defecate more often during exposure to the balloon stimuli than did the other horses. Additionally, the horses assessed by caretakers to have problems with ordinary care and/or training showed greater increases of HR and frequency of defecation in the balloon reactivity test, and the horses assessed as having `a long adaptation time to unfamiliar objects' were found to be unwilling to touch the balloons. Thus, the horses' behavior during the balloon reactivity test was highly consistent with their temperament as determined by the questionnaire. These results suggest that the questionnaire survey would be an effective means to assess equine temperamental traits, especially those related to anxiety.

Abstract: REASONS FOR PERFORMING STUDY: Short format 3-day events were introduced in 2004. Anecdotal reports suggested that horses were more tired on completion of the cross-country phase of short format events when compared with horses completing the cross-country phase of long format competitions, despite the absence of Phases A, B and C. OBJECTIVES: To compare the physiological parameters and haematological parameters of horses that had completed the cross-country phase of a short format (SF) and a long format (LF) CCI 2* competition. METHODS: During a CCI 2* competition 69 competitors took part in the short format and 74 in the long format competition. Long format competitors completed Phases A, B, C and D and short format competitors completed Phase D only. Phase D (the cross-country course) was identical for both competitions. Two-way ANOVA for repeated measures and post hoc tests were used to compare temperature, pulse and respiration rates of horses competing in both types of competition. T tests were used to compare mean lactate and electrolyte concentrations, while U-Mann Whitney tests were used to compare CK and AST levels measured in horses competing in the short and long formats of the event. RESULTS: Training schedules, age and previous competition experience were not significantly different between horses competing in the SF and LF competitions. On completion of Phase D, SF horses had significantly higher PCV and significantly lower ionised calcium concentrations when compared with LF horses. LF horses had significantly higher heart rates than SF horses 10 min prior to starting Phase D and immediately after completing Phase D; however, no other significant differences were found between the 2 groups of horses. CONCLUSIONS: Only weak evidence was found to support the hypothesis that the workload for the horse in a SF CCI 2* competition is significantly different when compared to the LF CCI 2* competition. POTENTIAL RELEVANCE: There is no beneficial or detrimental effect on horses that complete short format CCI 2* competitions as compared to those that complete long format CCI 2* competitions but further research is required into the physiological response of horses at CCI 3* and CCI 4* short format competitions.

Abstract: BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands improve human hypertension. However, the mechanism and site of this effect remains unknown, confounded by PPARgamma expression in many cell types, including endothelial cells (ECs). METHODS: To evaluate the vascular role of PPARgamma we used a conditional null mouse model. Specific disruption of PPARgamma in ECs was created by crossing Tie2-Cre+ transgenic (T2T+) and PPARgamma-floxed (fl/fl) mice to generate PPARgamma (fl/fl)T2T+ (PPARgamma E-null) mice. Conscious 8- to 12-week-old congenic PPARgamma (fl/fl)Cre- (wild type) and PPARgamma E-null mice were examined for changes in systolic blood pressure (BP) and heart rate (HR), untreated, after 2 months of salt-loading (drinking water), and after treatment for 3 months with high fat (HF) diet alone or supplemented during the last 2 weeks with rosiglitazone (3 mg/kg/d). RESULTS: Untreated PPARgamma E-nulls were phenotypically indistinguishable from wild-type littermates. However, compared to similarly treated wild types, HF-treated PPARgamma E-nulls had significantly elevated systolic BP not seen after normal diet or salt-loading. Despite sex-dependent baseline differences, salt-loaded and HF-treated PPARgamma E-nulls of either sex had significantly elevated HR versus wild types. Interestingly, rosiglitazone improved serum insulin levels, but not HF diet-induced hypertension, in PPARgamma E-null mice. CONCLUSIONS: These results suggest that PPARgamma in ECs not only is an important regulator of hypertension and HR under stressed conditions mimicking those arising in type 2 diabetics, but also mediates the antihypertensive effects of rosiglitazone. These data add evidence supporting a beneficial role for PPARgamma-specific ligands in the treatment of hypertension, and suggest therapeutic strategies targeting ECs may prove useful.