Study Evaluates Horseshoes, Track Type, Thoroughbred Safety

The authors ultimately suggested that trainers should place more emphasis on track type and maintenance than shoeing practices when it comes to keeping horses sound.

Photo: Anne M. Eberhardt/The Horse

It is the hope of every Thoroughbred racehorse trainer to have all of his or her charges put their best foot forward and win races with grace, finesse, and—most of all—without injury.

“Over the past several years, advances in the field of racehorse safety have focused on a number of variables, including the track surface-hoof interface,” explained Christie Mahaffey, PhD, of the Racing Surfaces Testing Laboratory in Orono, Maine. “We know that composition, cushion depth, moisture, temperature, and maintenance all can impact surface characteristics."

Some trainers try to optimize footing and control the track surface-hoof interface by using different kinds of shoes, such as those with toe grabs or heel calks or those with different weights and compositions. Some even choose different shoes based on track surface to manipulate traction.

To put some science behind trainers’ suppositions, Mahaffey and a team of racetrack surface researchers Mick Peterson, MS, PhD; C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, Dipl. ACVS; and Jeff Thomason, PhD, created dirt and synthetic track surface plots in a laboratory. They then used those plots, along with the “Orono Biomechanical Surface Tester,” to measure various loading rates that represented primary and secondary impacts of the hoof in a galloping horse wearing different aluminum racing shoes: a flat racing plate, a shoe with a serrated V-grip, and a shoe with both a 6 mm toe grab and 10 mm heel calks.

“Our study found that in a laboratory setting, shoeing had little effect on loading during the primary and secondary gait phases when the hoof comes in contact with the surface and slides forward,” Mahaffey said. “What was also really interesting is that changing the moisture content in the dirt surface did have a significant effect on the loading—much more so than using different shoes.”

She also noted that uneven localized loading of the shoe attachment points (i.e., where the shoes are nailed to the hoof) could potentially impact the different stresses and strains experienced by a racehorse in a “real-life” situation, meaning shoeing could still affect the racehorse's performance and safety.

“The laboratory system did not measure localized points equating to where the shoe is attached (at the nails), and there are other studies that demonstrated differences in strains through the hoof wall. Because we did not measure that, we cannot rule out the possibility that different shoes could still affect what a racehorse experiences,” said Mahaffey.

The study authors therefore suggested that trainers should place more emphasis on track type and track maintenance than shoeing practices when it comes to keeping their horses sound.

The study, “Dynamic testing of horseshoe designs at impact on synthetic and dirt Thoroughbred racetrack materials,” will appear in an upcoming edition of the Equine Veterinary Journal

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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