Six Standardbred (STB) mares (11+/-2 years, 521+/-77 kg; means+/-SD) performed an exercise trial (EX) where they underwent an incremental exercise test (GXT) as well as a parallel control trial (CON) to test the hypothesis that short-term, high intensity exercise would alter plasma concentrations of glucose, leptin, adiponectin, ghrelin, insulin and cortisol. Plasma samples were taken before (0 min), during (last 10s at 6, 8m/s, and the velocity eliciting VO(2max)), and after exercise (2, 10, 30, 60 min; 12 and 24h post-GXT). A second set of blood samples was collected before and after an afternoon meal given at 1515 h (at 1500, 1514, 1530, and 1545 h). Data were analyzed using ANOVA for repeated measures and Tukey's test. During the GXT, there were no changes (P>0.05) in the plasma concentrations of glucose, leptin, adiponectin or ghrelin. However, there was a 29% increase (P<0.05) in mean plasma cortisol concentration and a 35% decrease (P<0.05) in mean plasma insulin concentration. Substantial increases (P<0.05) in the mean plasma concentrations of glucose and cortisol of 36% and 102%, respectively, were seen in the EX trial during the first 60 min post-GXT. Plasma leptin concentration, measured at the 24h post-GXT time point, was 20% lower (P<0.05) during the EX trial compared with the parallel time point in the standing control (CON) trial. Plasma ghrelin concentration was 37% lower (P<0.05) in the EX trial compared with CON before and after the afternoon meal, but was 43% higher (P<0.05) 12h post-GXT. There were no differences between EX and CON for plasma concentrations of insulin or adiponectin during recovery. It was concluded that short-term high intensity exercise alters plasma leptin and ghrelin concentrations in STB mares post-exercise, which may signal the exercised animals to alter energy intake.
"Basal insulin concentrations will be increased by feeding concentrates, although they are generally unaffected by low-medium, non-structural carbohydrate (nSC) roughage (eg, soaked hay or hay with low to moderate nSC) (Borgia and others 2011). Physiological stress in the form of acute exercise or pain will generally decrease insulin concentrations in horses, most likely attributable to increases in circulating catecholamines that inhibit insulin (Gordon and others 2007). Contrary to popular belief, there is no evidence to suggest that pain (eg, associated with laminitis) increases basal insulin. "
[Show abstract][Hide abstract] ABSTRACT: Laminitis is one of the most common and frustrating clinical presentations in equine practice. While the principles of treatment for laminitis have not changed for several decades, there have been some important paradigm shifts in our understanding of laminitis. Most importantly, it is essential to consider laminitis as a clinical sign of disease and not as a disease in its own right. Once this shift in thinking has occurred, it is logical to then question what disease caused the laminitis. More than 90 per cent of horses presented with laminitis as their primary clinical sign will have developed it as a consequence of endocrine disease; most commonly equine metabolic syndrome (EMS). Given the fact that many horses will have painful protracted and/or chronic recurrent disease, a good understanding of the predisposing factors and how to diagnose and manage them is crucial. Current evidence suggests that early diagnosis and effective management of EMS should be a key aim for practising veterinary surgeons to prevent the devastating consequences of laminitis. This review will focus on EMS, its diagnosis and management.
British Veterinary Association.
08/2015; 177(7). DOI:10.1136/vr.103226
"In 1986, Alam and Dobson  noticed an increased cortisol level induced by rectal palpation of the reproductive tract in cows. In horses, increased cortisol levels have been associated with exercise  , transportation    , social stress , semen collection in stallions , hot-iron branding , and reproductive management in new environments  and therefore have to be considered as a disruption to homeostasis and stress. The analysis of cortisol in saliva is a noninvasive technique, which avoids confounding stress reactions of the animal induced by repeated venipuncture . "
"The neuroendocrine response to competition is thus complex and depends on subjective factors related to the cognitive evaluation of the situation rather than on the outcome itself . Exercise leads to an increase in cortisol, in humans as well as in horses      . However, by taking saliva samples during a board game competition in Japan, researchers found that changes in salivary cortisol after competition are associated with winning and losing, even if this game does not need physical exercise . "
[Show abstract][Hide abstract] ABSTRACT: During competition, stress may affect riders and horses. This stress can affect health, welfare, and/or performance. Our aim was to quantify stress levels during competition in horses and riders. We also searched relationships between these stress levels and performance. Twenty riders and 23 horses were followed up during a show-jumping event (26 courses) held at a riding school. Regular saliva samples taken from horses and riders were assayed to evaluate cortisol levels. We studied salivary cortisol evolution during the days of competition. There was no correlation between instantaneous sampling on horses and their riders. However, we did find a parallel between horse and rider salivary cortisol evolution curves, with a similar peak, reached 20 minutes after the course. The increase was stronger in riders than in horses. Correlations appeared between salivary cortisol concentration and performance, but stress in both partners seems to have an opposite influence on performance. Riders who showed a higher salivary cortisol increase were awarded more penalties, whereas horses that showed a higher increase in salivary cortisol performed better. Stress level measurement in rider–horse pairs would thus lead to improvement in competition conditions and performance, for horses as well as for riders.
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