Intense exercise can prove fatal to racehorses, study shows

May 4 (UPI) -- An examination of 1,713 cases of racehorse deaths in Ontario, Canada, suggests the intense exercise demanded by racing can prove fatal to a small percentage of horses.

The majority of deaths were linked with the most physically demanding races, short races featuring intense exertion. Theses types of races are the most common form of horse racing in North America.

Ontario's racing regulatory body, the Alcohol and Gaming Commission, requires all horse deaths within 60 days of a race to be reported. By examining the statistics, researchers were able to identify patterns that could help the horse racing industry improve safety standards and outcomes.

"The study reveals parallels between mortality and the intensity of the overall management of the horses, their lifestyle and the type of work they do," Peter Physick-Sheard, a researcher at the University of Guelph, said in a news release. "Training and racing at top speed within a short amount of time and space is a health risk for horses, as it would be for any other species, including humans."

Thoroughbred horses are the most likely to run short, intense races, and the latest analysis showed they're the most likely to perish as a result of racing. For every 1,000 thoroughbred races, 2.27 deaths were exercise-associated.

Quarter horses experienced 1.49 deaths per 1,000 races, while standardbreds suffered just 0.28 deaths per 1,000 races. For all breeds, musculoskeletal injury was the leading cause of death. Thoroughbred and quarter horses also experienced sudden death and fatal accidents.

The data, published this week in the Equine Veterinary Journal, also showed young stallions were more likely to perish during or shortly after a race than mares and geldings, or castrated male horses.

Researchers suggest additional studies could help identify why young stallions are at greater risk.

"It is possible that the very behavioral attributes traditionally seen as conferring a competitive advantage may have an overall negative impact," said Physick-Sheard. "We're starting to focus more on the things that are potentially inherent to the breeds of horse, as opposed to characteristics of the work they perform. As we get more insight into those horse factors, we become more aware of other influences that are possible causes of increased mortality risk."