When a racehorse is injured, one of the biggest concerns an owner has is whether or not the animal will be able to race again. The owner also wants to know if the horse will be able to perform as well as it did prior to being hurt. Travis Tull, DVM, and Hannah Wellman, BVSc, of Rood & Riddle Equine Hospital in Lexington, Ky., presented studies that addressed those questions during the Lameness-Racing session at the 2009 American Association of Equine Practitioners Convention. Both collaborated with prominent Rood & Riddle surgeon Larry Bramlage, DVM, MS, Dipl. ACVS, on the projects.

Tull reported on cumulative stress-induced injury of the distal third metacarpal/metatarsal bone in Thoroughbreds. According to Bramlage, the term commonly used for the condition is "bruising on the bottom of the cannon bones," and it can lead to condylar fractures if the affected horses remain in training. (A condylar fracture occurs in the bottom of the cannon bone at the level of the fetlock joint.)

In the past, horses suffering from the injury often were rested in their stalls. But the primary regimen for the 55 animals in Tull and Bramlage's study involved free exercise in the form of paddock turnout for 60 days. The turnout period was longer for some of the horses that didn't heal as quickly, and three of the Thoroughbreds had owners or trainers who didn't care for them as recommended.

Ninety-five percent of the horses in the study raced following their injuries and treatment, and 62% maintained or improved their class. Those results were better than results for Thoroughbreds that had received stall rest, according to Bramlage.

"One of the mistakes people commonly made was that they tried to restrict these horses' exercise by keeping them in their stalls," Bramlage said. "It's very much similar to the situation when you sprain your ankle and you just sit in a chair all day waiting for it to get better. You're better off if you loosen up your ankle every day and get the motion back in it."

For the low-level exercise regimen to work, horses need a paddock of an acre or more in size with grass, according to Bramlage.

"That's not too surprising because the horse has evolved as a grazing animal," the equine surgeon said. "They eat a few bites, walk a few steps, and then eat a few more bites. It's the kind of exercise they need to remodel their bones. If there isn't any grass, they just stand there after they finish rolling when you want them to be moving continuously."

Wellman discussed a study on base sesamoid fractures found in the radiographs of Thoroughbred sale yearlings.

"It's important to understand that these fragments aren't the same as chip fractures; they are markers for previous ligament injury," Bramlage said.

There were 37 yearlings with base sesamoid fragments in the study, and their racing records were compared to those of their maternal siblings. Seventy-eight percent of the horses that had fragments as yearlings started, and 73% raced more than once. Seventy-seven percent of their maternal siblings raced at least once by the time they were 3 years old.

But while the groups made it to competition at similar rates, their earnings differed significantly. The horses with sesamoid fragments as yearlings had average earnings per start of $1,859 compared to their maternal siblings' average earnings per start of $4,120.

"In general, they (the fragments) don't disable the horses, but horses race at a lesser class, we think because they can't train as hard," Bramlage said.

How those fragments affect a buyer's decision to purchase a yearling will depend on the buyer's expectations for the horse, according to the surgeon.

"The horse you are looking at will be a lesser racehorse than his siblings, but he still can be a useful racehorse," Bramlage said. "You look at the catalog page, and if you're trying to buy a bargain, the horse might be well worth your while. But, in general, you're not going to get a stakes horse or a high-quality horse. I've only seen one really good stakes horse that ever had that (a base sesamoid fragment as a yearling)."

About the Author

Deirdre Biles

Deirdre Biles is the Bloodstock Sales Editor for The Blood-Horse magazine.

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