When a racehorse turns in an unusually poor performance, the answer could lie in a physical problem

WHEN AFLEET ALEX loomed up alongside Giacomo at the head of the stretch in the Belmont Stakes (G1) on June 11, fans leaped to their feet, expecting one of the greatest moments in sport: the winners of the Preakness Stakes (G1) and the Kentucky Derby (G1), respectively, head to head in a battle to the wire that would go down in Triple Crown history.

But when jockey Mike Smith asked Giacomo to respond to the challenge, the Derby winner faltered, and Afleet Alex delivered a burst of speed that left the son of Holy Bull 173/4 lengths behind.

It was obvious to trainer John Shirreffs that something was wrong with Giacomo to cause the colt to tender such a poor performance. At first, feedback from Smith seemed to indicate the colt had displaced his soft palate, which causes obstruction of the airway. But when Giacomo was examined by Shirreffs's veterinarians in California, they could not find evidence of a displacing palate.

However, radiographs revealed bone chips in both front legs, and in late June the chips were removed arthroscopically. The Derby winner is scheduled to return to training after a 90-day layoff.

Quest for the cause

Dawn Hunkin, D.V.M., who performed Giacomo's initial physical examination upon his return to Hollywood Park, said that even if a horse is not showing individual symptoms considered serious enough to throw him off his game, a collection of minor complaints added together could cause performance problems, so a thorough workup is needed to uncover the answer.

"Oftentimes with poor performance, it's a more complex issue, and there often is more than one problem," Hunkin said.

Hunkin, who is a practitioner with Von Bluecher, Prida, Blea Equine Medicine and Surgery, based in Southern California, recommends beginning the evaluation with a thorough physical examination that includes taking a complete history of the horse.

"Generally, we start with a physical examination to look over the horse and see if there is anything in the overall health or level of fitness that might have affected performance," Hunkin said. "We jog them up and down the shedrow to make sure they're sound; we examine their legs, look over their entire body. Then we usually will do some laboratory work to make sure they're not sick." In addition to a general physical examination, Hunkin typically examines the respiratory system for evidence of exercise-induced pulmonary hemorrhage (bleeding), airway problems, or infection.

"We would listen to the lungs, perhaps do endoscopy, and sometimes we will take X-rays of the chest," Hunkin said. "If we don't find anything on endoscopic examination or by listening to the lungs, we have the option of sending them for a treadmill evaluation."

High-speed treadmill

"We can evaluate any and all kinds of exercise-related problems, whether they are upper airway or cardiac," said Jennifer Brown, D.V.M., who uses an in-ground, high-speed treadmill capable of up to 60 mph and a full diagnostic array to analyze heart, respiratory, and gait problems in horses referred to the treadmill laboratory at the Marion duPont Scott Equine Medical Center in Leesburg, Virginia.

Among those diagnostics is video endoscopy for diagnosing respiratory problems and a video gait analysis system consisting of five video cameras positioned around and over an exercising horse on the treadmill. Gait is analyzed using markers placed at strategic points on the horse's body that enable the cameras to record the horse's footfalls, foot placement, and way of going to determine subtle gait abnormalities.

"We do all sorts of treadmill work," Brown said, "[including a] full exercise evaluation of horses that are quitting in races, showing some sign of exercise intolerance, making a [breathing] noise, or that seem to have airway problems. We do our best with the treadmill to simulate a racing experience for the horses, but, of course, it's not exactly like it, so there are some things that we can't consistently reproduce on the treadmill, but we certainly work hard to identify whatever problems they are having."

"We do a lot of upper airway surgery with the laser for problems we identify on the treadmill. So we go start to finish to get these horses back to performance."

Previously at Michigan State University, Brown worked with Frederik Derksen, D.V.M., Ph.D., to pioneer a method for diagnosing upper airway problems by recording and analyzing breathing sounds of an exercising horse. A special microphone is placed on a noseband three to six centimeters from the horse's nostrils while it exercises on the high-speed treadmill. Spectrogram analysis of the voice print can reveal subtle breathing noises before they can be heard by the human ear, thus enabling early intervention to resolve the problem.

Lameness examination

A lameness examination entails jogging the horse to observe any lameness or gait abnormalities; palpation of the limb to detect swelling or heat; and flexing of the joints to assure they are functioning properly without pain. Areas of concern are radiographed or ultrasounded to look more closely at bones and soft tissues.

Diagnostic nerve blocks, which numb a portion of the limb where the veterinarian suspects the horse's pain originates, may be used to narrow the search.

"We use a lot of nuclear scintigraphy," Hunkin said of the radiographic procedure that employs a radioactive isotope administered intravenously and a gamma ray-sensitive camera to produce images that are then interpreted by a nuclear computer. The computer generates a scintigram that shows any concentration of the tracer isotope, which indicates changes in the bone, as a "hot spot" or dark area on the film. Areas of compromised blood flow are identified as "cold spots."

"I think nuclear scintigraphy has given us a big advantage in that we often are able to identify stress fractures before they become complete fractures. In that way, we have decreased the number of catastrophic fractures," Hunkin said. "Now we're able to see things that we never would have known a horse had without scintigraphy. For example, we often will see evidence of increased [bone activity] in the tibia, pelvis, or perhaps the humerus in the shoulder that we might not have noticed otherwise until it was a catastrophic injury."

Scintigraphy has proven invaluable in the detection of microfractures, small stress cracks in the bone that are not detectable through standard X-rays. Even subtle changes in the bone can be detected by comparing scintigrams of opposite legs and then noting asymmetrical differences in tracer distribution between the two legs.

Get everyone involved

Hunkin often involves the horse's farrier in an evaluation, as well as the trainer, the groom, the exercise rider, and the jockey.

"Getting input from all these people is really important because they each offer an individual perspective," Hunkin said. "We try to work as a team as much as possible."

While physical ailments can be detected using various diagnostic procedures, talking to the people who work with the horse on a day-to-day basis is the only way to gain insight into changes in his attitude that might impact performance.

"If a horse is sour, that is a portion of his overall well-being," Hunkin said. "Some horses, especially in California because we race year-round, don't get a vacation. And if they do, it's a matter of a few days to a week of walking the shedrow, but they're still at the racetrack; they aren't turned out in a field. So the stress level is still there.

"Some of the things we want to rule out are problems related to stress, such as attitude or just needing some time off," Hunkin said. Among those stress-related conditions are gastric ulcers, which are caused by a combination of physical and mental stress. Ulcers cause gut pain and may precipitate behavioral problems as well as anorexia and an overall unthrifty condition.

"We don't scope as many horses as we used to, looking for ulcers, because it has been well established that a large percentage of horses suffer from gastric ulceration," Hunkin said. "So most times we just treat them [with anti-ulcer medication] and use the response to treatment as an indication of the problem." Tapeworm infestation can mimic many symptoms of gastric ulcers, so it is important to treat the horse with praziquantel (Equimax, Zimecterin Gold) or a double dose of pyrantel pamoate (Strongid paste) in addition to treating for ulcers.

Precaution before turnout

Hunkin urged owners and trainers to have a veterinarian examine every horse they are contemplating turning out or laying off, even one that is not showing any obvious signs of injury or ill health. A horse that is wound tight and racing fit often explodes with a burst of energy when turned out and may injure himself, especially if he has an undiagnosed musculoskeletal problem that gives way when the horse is bucking, jumping shadows, and dashing around a turnout area on uneven footing.

"Most of the time, horses are getting time off because we've gone over them and have suggested that is the thing to do," Hunkin said. "In the majority of cases, we will work the horse up before that happens.

"The other issue is that if you turn a horse out without addressing a problem that should have been taken care of before he was turned out, it becomes a matter of lost time and lost income. For example, if you have a horse that's lame and has filling in his fetlock and you decide to give him a month off, the truth might be that the horse has a chip fracture in that fetlock, and it could have been removed and you could have used that time for the recuperative phase.

"Instead, some people will lay the horse off, put him back into training, and then discover he needs surgery. And they've wasted all that time and money laying him up without addressing the problem."