A study of fatigue in long-distance endurance horses might offer some helpful insights for trail riders who ride for shorter distances.
In a study conducted by the University of California-Davis, researchers analyzed almost 3,500 records of horses competing in endurance rides. These rides were sanctioned by the American Endurance Ride Conference and all horses were required to have veterinary checks every 10 to 20 miles throughout each race, which ranged in distance from 25 to 100 miles. Horses were eliminated from the competition if they were found to be lame or showed signs of significant fatigue.
For the horses whose records were examined, 19% were eliminated for some reason before completing the race. About 47% of eliminations were because of lameness. The next most common reason for elimination was a metabolic cause such as delayed capillary refill or slow cardiac recovery at a vet check. Horses that showed some metabolic signs early in the race, but were allowed to recover and then continue, were at an increased risk of being eliminated later in the race. In addition, horses with abnormal gut sounds at some point in the first half of the race were more likely to be eliminated later for metabolic reasons.
The researchers pointed out that a rider should be alert to early signs that a horse is getting tired, and should be willing to cut short a planned ride if his horse seems to be heading toward fatigue, thereby avoiding serious metabolic problems. This is especially true for so-called “weekend warriors” who may not have brought their horses into condition through a slow, progressive program of increased exercise before embarking on sporadic long rides.