The change might be subtle—a missed lead change here and there or a less significant extension. It could also be more noticeable—uneven gaits, rampant tail swishes, bucks, or other conflict behavior. Whatever the difference, it’s often easy to tell when your horse isn’t performing up to par. What’s sometimes not as simple, however, is determining why.

At the American Association of Equine Practitioners’ Focus on Poor Performance meeting, held Sept. 10-12 in Lexington, Kentucky, Elizabeth J. Davidson, DVM, Dipl. ACVS, ACVSMR, reviewed how veterinarians evaluate these horses and help them return to full function. Davidson is an associate professor of sports medicine at the New Bolton Center, the University of Pennsylvania School of Veterinary Medicine’s large animal hospital, in Kennett Square.

“Many body systems must be functioning properly for a horse to do what we ask of them on a daily basis,” Davidson said. And when one or more of those systems break down, the horse isn’t able to perform to his full potential.

In many cases, she said, affected horses’ performance decreases gradually, and they often don’t have any distinct clinical abnormalities. “For these horses, investigation into the cause(s) of poor performance can be a real challenge. This is where the real detective work begins.”

A veterinarian’s ultimate goal with a poorly performing horse is to return the patient to full function, which requires the appropriate treatment. Thus, he or she must first narrow the possible causes to get a good idea of where to start.

Davidson also stress