Uneven Feet in Sport Horses Related to Other Conformation Traits

A research team from The Netherlands analyzed the conformation, genetic, and performance records of 44,840 Dutch Warmbloods competing at the top levels of dressage and show jumping to determine if uneven feet (one forefoot that is differently shaped than the other) affect a horse's performance career, and if this trait is related to other conformation traits. They found uneven feet are not highly heritable, and the conformation of the forelimbs (such as heel height and pastern angle), height at the withers, and neck length also contribute to the prevalence of uneven feet in the Dutch Warmblood population.

In the study population, they found that tall horses with short necks are more likely to develop uneven feet.

"We noticed that uneven feet were occurring more and more in the sport horse population, and we wanted to find out if there is a genetic reason, or if something in horse management practices is causing one forefoot to develop differently than the other," says Bart Ducro, PhD, of the Animal Breeding and Genomics Group of Wageningen University, The Netherlands.

Injuries of the forelimbs are the main reason for early retirement of sport horses, and uneven feet are more prevalent in lame horses than in sound ones.

The researchers found that uneven feet are weakly heritable, meaning that there is more likely another reason for this trait. This increase in uneven feet in the study population over time seems to indicate that uneven feet may develop as the horse grows.

"Foals have a preference for standing on one foot or the other while grazing," according to Ducro. "In humans, we would call this right- or left-handedness."

A shorter neck and greater height at the withers might cause an uneven weight distribution in the growing foal, which causes the hooves to grow at different rates. There was a correlation between uneven feet, the height of the withers, and the neck length; uneven feet were more often associated with tall horses with short necks.

"Selection for better conformation favors taller horses," says Ducro. In these horses, the neck is relatively shorter, apparently leading to disproportional growth.

The study underlines the need for care in breeding programs and managing young horses. "In general, in managing sport horses, treat conformation as one of the risk factors for early retirement," says Ducro.

Checking early to see if a foal has a preference for weight-bearing on one or the other foot while grazing can help offset the development of uneven feet. Feeding on a pasture with higher grass, for example, will cause less pressure on the legs because the foal with a short neck and long legs can hold its head higher while grazing. Proper shoeing at an early age can also help to prevent further development of uneven feet.

The study is published in the Equine Veterinary Journal, (2009) 41(2) 139-143 by B.J. Ducro, H. Bovenhuis, and W. Back.

About the Author

Nancy Zacks, MS

Nancy Zacks holds an M.S. in Science Journalism from the Boston University College of Communication. She grew up in suburban Philadelphia where she learned to ride over fields and fences in nearby Malvern, Pa. When not writing, she enjoys riding at an eventing barn, drawing and painting horses, volunteering at a therapeutic riding program, and walking with Lilly, her black Labrador Retriever.

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