Endurance veterinarians detect physiologically compromised horses in a 160 km ride.

The research article is about a study conducted to examine the physiological changes in endurance horses during a 160 km ride, and how these changes can indicate whether a horse is metabolically compromised.

Research Objective and Method

• The objective of the research was to investigate changes in physiological, haematological and biochemical variables in endurance horses as they undertake a 160 km ride. The researchers posited that horses identified as metabolically compromised during veterinary inspections would show significant differences in these variables compared to horses that complete the ride successfully.
• The study involved the monitoring of forty-eight horses participating in the Australian Tom Quilty 160 km endurance ride. Prior to the ride, during the ride, at the ride’s end, and the following morning, the horses were weighed and their blood samples were collected. The blood samples were subjected to analysis to measure parameters such as electrolytes, packed cell volume (PCV), plasma protein and acid-base variables.
• The statistical analysis of gathered data was done using multinomial logistic regression and repeated measures ANOVA.

Results from the Investigation

• Out of the forty-eight horses, only eighteen successfully completed the ride, sixteen were eliminated due to lameness, and ten were removed for metabolic reasons. The riders voluntarily withdrew four horses.
• It was observed that horses identified as metabolically compromised (VOM) had a lighter pre-ride bodyweight, suggesting that this factor could potentially predict which horses are more likely to become metabolically compromised during endurance riding.
• All horse groups showed an increase in PCV and total plasma protein mid-ride compared to pre-ride values. The increase in PCV was significantly greater for the VOM horses compared to other horses.
• There were noticeable changes in blood concentrations of sodium, chloride, and calcium over time and across the different groups of horses. The VOM group had lower mid-ride sodium and chloride levels compared to the successful completers (SC) and the lameness-eliminated (VOL) horses.

Research Conclusions

• The study concluded that horses classified as VOM weighed less prior to the ride and exhibited more dehydration and greater electrolyte depletion mid-ride, when compared to the SC or VOL horses. This affirms the study hypothesis that there are significant physiological and biochemical differences in horses that become metabolically compromised during a long-distance endurance ride.