Hoof Pain and Performance

When a performance horse slowly goes off form, any number of things can be the cause. Could he have ulcers? Is he being overtrained? Is something subtle and mysterious going on with his metabolism? The problem could be much simpler than that--his feet might just hurt.

A racehorse's feet and legs are subjected to unbelievably high stresses during racing. At the 2002 American Association of Equine Practitioners convention, Dr. David Nunamaker reported that peak bone strains in horses are higher than those previously reported in any animal species. When this level of stress over time is applied to the horse's foot, there are bound to be structural changes. The challenge is in preventing changes that impact performance (ideally) or shoeing an affected horse to get the foot back into a more functional conformation.

A good example is 5-year-old Early Flyer, who hadn't won a race in two years. A son of Gilded Time, Early Flyer is a grade II winner who placed in a grade I race as a 3-year-old. But he had no stakes wins or places as a 4-year-old. During that year, Dave Fiske, manager of Oakwind Farm near Lexington where Early Flyer was bred and kept, said the horse "gradually, race by race, went off form. No one could say what was wrong with him. Blood tests, bone scans, X-rays, everything was negative."

Fiske then had Early Flyer examined by veterinarian Ric Redden, founder of the International Equine Podiatry Clinic in Versailles, Ky."He knew exactly what was wrong," Fiske said. "He brought out (Early Flyer's) X-rays, protractors, rulers, and felt pens to give me a 90-minute tutorial on what the horse's measurements were and what they should be."

See Early Flyer's feet before and after correction here.

Redden said a decreased ground plantar angle, or the angle the wings of the hind foot's coffin bone make with the ground, was hampering the horse's ability to run. Normally the plantar angle is five to eight degrees, but Early Flyer's hind feet were at minus five degrees--the toes of the coffin bones were tipped up instead of down. Both front and hind feet were affected, but the hinds were more severe.

To see what effects this might have on race times, imagine running in shoes with thick soles at the toes and thin soles at the heels. It will be a lot tougher to break over that elevated toe than it would be with your regular running shoes.

This biomechanical disadvantage not only can result in slower times, but also in inappropriate stresses in the heel and in the muscles that are trying to compensate for the poor angle. Many horses have decreased plantar and palmar (same as plantar angle, but in the front feet) angles because of the stress from hard use, Redden said. The decreased angles indicate compression of the digital cushion that normally helps absorb and dissipate the shock of impact, but that cushion can't do much when it's crushed (think of a beaten down feather pillow)."

"They don't run too good with flat tires," commented Redden.

Muscle soreness from the increased work required to run with poor angles can also result. Fiske said Early Flyer had chronic, apparently severe, soreness in his back and hips prior to Redden's treatment.

Fixing the problem in this case doesn't just involve fixing the feet, it involves fixing the bone angles. Correcting the feet is the means to the end, not the end itself. The key is using radiographs that show the angles before and after shoeing, so a farrier can see what needs to be done and how well it's working.

Redden treats horses like Early Flyer by shoeing them to raise the palmar and/or plantar angle back into the normal range. He does this with his "rock and roll" shoe, which has a curved ground surface that allows the horse to break over more easily and raise or lower his heels at will. This is quite different from a typical flat shoe, which locks the hoof into that angle whenever there is weight on the foot.

With this shoe, the horse can (and does) change the angles of his feet almost constantly even while standing still, with the little movements of balancing. These angle changes affect the load on the various inner foot structures, in effect massaging the circulation that is compromised with a crushed heel.

"Instead of pushing the heel into place with a wedge (pad), we're letting him pull his foot into place with the rock and roll shoe," Redden said. "It's 24-hour healing."

The improved blood flow allows the crushed digital cushion and hoof wall at the heels to heal and grow more tissue, gradually reversing the low heel. It certainly worked for Early Flyer: Four to six weeks after Redden's first corrective shoeing job on the horse, Early Flyer had more wall and sole depth than before, even with a continuation of light training.

"He also had none of the soreness over the back and hips that he had always had," Fiske said.

On Jan. 31, nearly five months after the first shoeing correction, Early Flyer ran a disappointing fifth in a six-furlong allowance race, but not because of his feet.

"We thought we'd probably run a short horse," said Fiske.

On March 3, Early Flyer returned to his 2001 form with a six-furlong allowance win in 1:10.53 at Fair Grounds.

"He had never won at that distance before, and he won it in the mud, which he'd never raced in before," said Fiske. "He led early, then got overtaken a bit and bumped, but he still came back to win. He hasn't been sore for months."

Pleased with Early Flyer's response to Redden's therapeutic shoeing principles, Fiske nevertheless wants to keep horses from getting to the point of losing form and having to come back. To combat degenerating feet, he is now having selected horses (some in training, some broodmares, and some yearlings) radiographed before and after shoeing. "We're just now starting this up," he said. "It's kind of an uphill battle getting everyone on board -- trainers, farriers, or whoever. We're trying to do some serial radiographs to follow progress; in some cases, the progress is quite dramatic."

"You have to know what you're dealing with before there's a problem; otherwise it's not preventive," said Redden.

"The rationale is that with this preventive approach, you will get horses with fewer foot problems that will be able to train more aggressively and stay sounder longer," added Fiske. "Hopefully along the way they will get faster, and you hope you can race them more often. If they don't hurt, they'll be happier, healthier, and want to be racehorses."

About the Author

Christy M. West

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from TheHorse.com. Learn More