To make the most of natural athletic ability, your horse needs soundness and good health. | © Amy K. Dragoo

• An honest jumper begins to refuse fences. 

• A seasoned event horse runs out of steam during cross country and has to withdraw. 

• A young dressage prospect struggles with collection, and you wonder if upper-level movements will be beyond him.

Disappointing and frustrating are the words for situations like these. The horse has the talent for top-level competition. You’ve worked with your trainer to make sure he has the foundation he needs and that your riding doesn’t interfere with his performance. You’ve tinkered with his program—tried riding out more, turning him out more, schooling more, giving him more days off—but he’s still having problems. Does he just not have what it takes? Or is a physical problem holding him back?

To identify a performance-limiting issue, your veterinarian may start by taking a detailed history of everything that’s been tried to address the problem. | © Dusty Perin

Many things—genes, conformation, temperament, growth and development—determine a horse’s natural athletic ability. To make the most of that ability, he needs careful training and a skilled rider. He also needs soundness and good health. Unrecognized physical conditions often keep horses from achieving full potential or even matching their previous performance, says sporthorse veterinarian Elizabeth Davidson, DVM, of the University of Pennsylvania’s New Bolton Center. The source of the trouble can be hard to pin down. In this article Dr. Davidson explains how to find it. 

Where to Begin

People are quick to suspect poor fitness or the stress of work when a horse’s performance doesn’t match expectations. But for most horses in most sports, Dr. Davidson says, these are not the most likely causes. “A physical problem is a more likely reason for poor performance than either general stress or lack of fitness,” she says. 

A horse clearly has to be fit for the level of work he’s asked to do. But outside of a few sports—racing, endurance, upper-level eventing—horses generally don’t need high fitness levels or arduous conditioning programs, she explains. “We like to think that show hunters are working hard, but they are not maxed out from a cardiovascular standpoint,” she says. “Unless there’s a mismatch between the horse’s regular exercise program and the expectation for what he’ll do in competition, fitness isn’t the first thing you’d think of as a cause of poor performance.” If you ride your horse regularly in a variety of activities—schooling mixed with trail rides; brief, intense work mixed with long, slow work—and give him ample turnout, chances are he’ll be fit enough for all but the most demanding sports.

Similarly, the sort of work stress known to drag down human job performance may not be much of a factor for horses. If your friend says she’s overworked, she likely means that she’s mentally stressed by her job or her demanding schedule. “We can’t assess a horse’s mental state,” Dr. Davidson says. 

Blood tests may point to chronic inflammation, infection, damage to muscle or liver tissue, anemia and other conditions. | © Dusty Perin

Hard work can cause wear and tear on a horse’s body, though. If you’re confident that your horse is fit and trained for his sport but his performance is still subpar, it could be time to enlist your vet.

Getting to the bottom of the problem calls for a whole-body approach, Dr. Davidson says. She starts with a detailed history to find out everything that’s been tried—medications, supplements, feeding changes, tack changes, modifications to shoeing, changes in work—to address the problem. That’s followed by a thorough physical exam, covering the horse head to tail. She listens to the horse’s heart and lungs with a stethoscope; checks the back, each limb and each foot for abnormalities and sensitive areas; and watches the trot. Blood tests are part of the exam, too. They may find evidence of chronic inflammation, infection, damage to muscle or liver tissue, anemia and other conditions. 

The history and the physical exam guide the next steps. Depending on what they show, the focus may narrow to one of the following areas.

Joints and Muscles 

A horse who catches rails at heights he used to clear easily may have an unrecognized musculoskeletal problem. | © Amy K. Dragoo

“Unrecognized musculoskeletal problems are the most common cause for poor performance in the horses we see,” says Dr. Davidson. Horses often soldier on with subtle injuries, showing no obvious lameness. Your horse could be doing that if he:

• Moves less freely or with shorter strides.

• Resists bending in one direction.

• Struggles with lead changes in one direction or the other or swaps late behind. 

• Lacks “push,” resists engaging his hindquarters or seems uncomfortable in collected work.

• Jumps flat or no longer folds his legs tightly.

• Starts refusing or darting at jumps or pulls rails at heights he cleared before. 

• Resists traveling up or down hills.

• Acts grouchy when he is asked to move forward.

While some of these signs may stem from training or behavioral problems, they suggest discomfort. The horse could be developing a joint or tendon problem that’s still too mild to make him clearly lame; a back or neck problem, such as sore muscles or abnormalities of the spine; or even early-stage neurologic disease. Muscle disorders such as polysaccharide storage myopathy, which can lead to tying up, are another possibility. 

What to do: Without specific signs like lameness or heat or swelling in a particular place, Dr. Davidson says, it’s challenging to pinpoint the trouble site. The veterinarian will do an in-depth lameness exam to detect faint signs that may have been overlooked—slight abnormalities in gait or signs of mild soreness or inflammation. She’ll palpate the limbs carefully and move the joints through their normal range of motion to check for stiffness, comparing opposing limbs. She’ll look at the muscling of the neck, back or hindquarters for differences between right and left, as muscles shrink with lack of use. She’ll watch the horse trot on a straight line and in circles in both directions and, perhaps, on hard and soft ground, on a slope or with and without a rider. 

“Some problems are evident only in certain conditions—only when the horse is ridden or only when he’s ridden for half an hour or more or only in certain maneuvers, like canter pirouettes in one direction,” Dr. Davidson says. “The vet may ask you to ride the horse and replicate those conditions.” To make a subtle lameness more apparent, she may perform flexion tests, holding a joint flexed for 45 seconds or so before the horse is trotted off. If she suspects a musculoskeletal problem, she may use injections of local anesthetic (nerve blocks) to locate it. 

If the exam points to a specific region, imaging may reveal what’s going on. Ultrasound scans can highlight damaged tendons or ligaments, and X-rays show bone problems. Magnetic resonance imaging and computed tomography scans produce detailed views but require a trip to a clinic with specialized imaging equipment. 

If it’s still not clear where the problem lies, different tools may help. Blood tests and muscle biopsies are used to diagnose muscle disorders. A bone scan (nuclear scintigraphy) highlights areas where bone disease is active. It can turn up conditions from tiny stress fractures to joint degeneration. This scan, done at a clinic, is helpful in locating problems in the upper body and topline, where thick muscle layers mask heat and other signs of inflammation in underlying bones and joints. 

Nuclear scintigraphy highlights areas where bone disease is active. | © Dusty Perin

Keep in mind: The treatment and the outlook for your horse will depend on what the investigation finds. Whatever it is, catching the problem early is your best shot at keeping it from limiting his career. 

Breathing

The muscles that power performance depend on oxygen that the horse takes in with each breath, so anything that limits the intake is important. Respiratory problems are the second most common cause of poor performance that Dr. Davidson sees. “The horse may have a partial obstruction in the upper airway or inflammatory airway disease in the lower respiratory tract,” she says.

Coughing, nasal discharge and respiratory noise are the usual signs of respiratory illness, but you won’t always see them. Instead, your horse may:

• Tire quickly when he’s asked for extended effort.

• Take longer to recover from a gallop than he previously did.

• Have trouble maintaining collection.

• Breathe noisily during exercise.

The most common upper-airway obstruction is laryngeal hemiplegia (paralysis on one side of the larynx), better known as “roaring” for the distinctive sound the horse makes as he breathes. Some other problems also produce odd noises, but a horse can have an airway abnormality without any unusual sound. The nature of the problem and the type of work the horse does determine how much he’s affected. An upper-airway obstruction may be a serious handicap for an event horse because he has to make a big effort over an extended time in cross country. A dressage horse may tire in collected work if flexion adds to his airway restriction. But a jumper, who puts out short bursts of effort, may not be so troubled. 

Gastric ulcers, which are common in performance horses, are diagnosed with an endoscopic exam. | © Amy K. Dragoo

Chronic problems in the lower respiratory tract (the lungs and bronchial tubes) can also sap performance. Inflammatory airway disease often develops in young horses in training. “It can appear at first without a cough and mucus,” Dr. Davidson says. Recurrent airway obstruction (heaves) usually appears in horses in their teens. Irritants—dust, mold spores and gases like the ammonia produced when urine breaks down—trigger both conditions. In IAD the irritants produce inflammation, and high-performance activity feeds it. Heaves is thought to be an allergic response similar to human asthma.

What to do: Upper-airway obstructions are diagnosed with endoscopic exams, Dr. Davidson says. These exams can be done with the horse standing or exercising on a treadmill or over the ground with a rider, which is useful if the problem shows up only when the horse is working. Laryngeal hemiplegia and many other upper-airway abnormalities can often be corrected with surgery.

A test called bronchoalveolar lavage is helpful in diagnosing IAD and heaves. The veterinarian uses a catheter to place a bit of sterile fluid into the lung and then draw it out for analysis. The results provide clues to the degree and type of inflammation. Pulmonary-function tests are sometimes done to see how well the lungs are doing their job, but these tests are available only at a few major clinics. 

Rest and medication (a bronchodilator to open the airways or a steroid to reduce inflammation) can help a horse recover from an episode of airway inflammation, but the problem is likely to return unless you reduce or eliminate the irritants that trigger it: 

• Feed the horse a hay substitute, bagged chopped hay or steamed hay. Hay is the main source of the dust and mold spores that cause the problem. 

Bit pain can cause a horse to loll his tongue, which can restrict airflow, when you ride. | © Dusty Perin

• Store hay in a separate building. 

• Don’t use straw—another dust and mold breeder—for bedding.

• Clean barn aisles the old-fashioned way, by sprinkling with a watering can and sweeping, not with a blower. 

• Open barn windows and run fans to move clean air through.

Keep in mind: If these steps aren’t enough for a horse with IAD or heaves, try moving him out of the barn to a run-in shed in the pasture.

Nutrition and Digestion

Your horse needs a feeding program that meets the nutritional requirements for his workload. If he is getting plenty of good-quality hay and a balanced commercial concentrate, is in good weight and has a shiny coat, he is probably getting what he needs. “As a rule, nutritional problems do not affect most well-managed horses,” Dr. Davidson says. However, some types of horses are more likely to have issues than others. “Elite upper-level eventing or endurance horses are most susceptible to nutritional deficiencies.”

What to do: If you think your horse’s diet could be part of his problem, review it with your veterinarian or with an equine nutritionist. Regional Cooperative Extension offices and many feed companies offer free consultations. 

Reaching for a supplement isn’t the best first step, says Dr. Davidson. Some products claim to improve performance, but there’s little scientific evidence to back up the claims. “Some supplements have ingredients like yucca that are low-grade anti-inflammatories, so any improvement you see might be due to the anti-inflammatory rather than nutritional effects,” she says. You’d be better off finding and treating the cause of inflammation.

“Most competition horses are oversupplemented, and that poses risks,” she adds. For example, she says, upper-level event and endurance horses are sometimes given excessive levels of electrolytes, and this can interfere with normal body functions. 

Keep in mind: Gastric ulcers are common in competition horses. “It’s not clear how much they affect performance. There are studies showing that nearly all racehorses develop ulcers, but the condition doesn’t always slow them down,” Dr. Davidson says. “Still, if your horse has ulcers, you’ll want to treat them.” Ulcers are diagnosed with an endoscopic exam and treated with medication and changes in management. 

Infection

While most infectious diseases produce obvious signs—the horse goes off his feed, becomes lethargic, runs a fever and develops respiratory or intestinal symptoms—some are subtler. Lyme disease is notorious for vague signs such as shifting soreness, lack of energy, a depressed or cranky attitude and hypersensitivity to touch. If you live where this tick-borne disease is prevalent, it should be on your suspect list. 

What to do: To diagnose Lyme disease, your veterinarian will perform a thorough physical exam and draw blood to test for antibodies to the bacteria that cause the disease. (The antibodies may not appear for several weeks after the initial infection, making diagnosis tricky.) The antibiotics doxycycline (oral) and oxytetracycline (IV) are effective, especially when the illness is recognized and treated early. 

Keep in mind: When Lyme disease isn’t treated promptly, there’s a greater risk of lingering effects and lasting damage to joints and other areas. 

Tack Trouble

Poorly fitting tack can directly affect a horse’s way of going and, over time, make him sore. 

What to do:

• Have a pro check the fit of your saddle at least once a year. It may have been perfect for your horse initially, but the shape of his back changes as he gains or loses weight and muscle. 

• Position the saddle so that it doesn’t sit on the shoulder blade and allow space between the girth and the foreleg. If the saddle is too far forward, it will interfere with shoulder movement, and if the girth passes directly behind the elbow, it will pinch the pectoral muscles. 

• An uncomfortable girth can also restrict movement even when correctly placed. Try one that’s a bit wider, to spread the pressure, made of a softer material or shaped to conform to the horse’s anatomy. It should have elastic on at least one end. 

Keep in mind: Bit pain can cause a horse to fight rein contact, toss his head or loll his tongue (which can restrict airflow) when you ride. Be sure your horse’s bit fits comfortably and his bridle is adjusted so that the bit rests in his mouth correctly. If you’re not sure, ask your trainer or your veterinarian to check. 

And More… 

Other factors can contribute to poor performance. Your horse might have a dental or vision problem. He might need a change in the way his feet are done. 

“Take a team approach. Your trainer, veterinarian and farrier can each add pieces to the puzzle. You may also need to consult veterinary specialists in equine vision, dentistry or sports medicine,” Dr. Davidson says. “Getting to the answer can be a challenge because you won’t find one expert for all the possibilities. It often requires a comprehensive approach to unlock the causes of poor performance.”

This article originally appeared in the January 2015 issue of Practical Horseman.