Knowing risk factors can help veterinarians, riders, and trainers make informed decisions to safeguard endurance horses' welfare. That doesn’t mean people can change certain things—such as rider or horse sex, for example—but rather pay attention to the elevated risks. | Photo: Anne M. Eberhardt/The Horse

If your endurance horse is a stallion, older than 9, and competing in a ride against more than 60 other horses, he’s at increased risk of being eliminated from the race due to lameness at an obligatory veterinary check. And if you, the rider, are male, the risk is even higher.

That’s one of the main findings from a recent study in which researchers in the U.K. investigated risk factors for vet check failures in endurance horses. Their recent study focused on data from all Fédération Equestre Internationale (FEI) endurance events held worldwide from 2010 and 2015—nearly 83,000 starts.

Meanwhile, a race distance of more than 100 kilometers (about 62 miles) is associated with an increased risk of vet check failure due to metabolic issues such as cardiac problems, high temperatures, or respiratory distress. Having a male rider increases the risk of a metabolic issue during a race by 82% compared to female riders, said Euan David Bennet, PhD, research associate in the Weipers Centre for Equine Welfare in the School of Veterinary Medicine at the University of Glasgow, in Scotland