Investigating and treating poor performance in sport horses

Veterinarians have an integral role to play when horses fail to perform at an expected level.

Performance relies on many factors that all work together and cannot easily be divorced from one another. Most poorly performing horses have several different problems that are contributing to the loss of performance. Equally, many horses continue to perform at a very high or expected level while suffering from multiple performance-limiting factors.

If the author has learned anything from both competing and treating horses, it is that it takes a lot for a horse to get to a point where it no longer chooses to cooperate with its rider, and that problems are often multifactorial.

Horse factors

Musculoskeletal discomfort is by far the most common underlying cause of decreased performance in sport horses.

Any equine practitioner will attest to the astonishingly large proportion of ridden horses that are lame. Almost 50% of sport horses in normal work may suffer from a degree of lameness, often without their owners or riders noticing.

The ridden horse ethogram developed by Sue Dyson incorporates 24 behavioural factors that, when viewed in combination, can assist riders and trainers to detect musculoskeletal pain earlier, and more accurately. Out of the 24 behaviours, lame horses display a median of 9 (with a standard deviation of 2) and a maximum of 14, while non-lame horses show a median of 2 (with a standard deviation of 1.4) and a maximum of 6 of these behaviours.

A subset of these behaviours also occurs much more commonly in lame horses. Lame horses are much more likely to work with their ears back, mouths open, tongue out, display head-tossing or tilting, resist work and forward movement, be crooked, hurry, change gait spontaneously, have a poor-quality canter, stumble or drag their toes (Dyson et al, 2018).

Specific injuries are also more and less common (and more or less significant) depending on the sport (Table 1).

In addition to musculoskeletal discomfort, a variety of other veterinary problems exist that can cause poor performance. These include gastric ulceration, airway inflammation, disorders of muscle metabolism (for example, polysaccharide storage myopathy), other metabolic diseases (such as equine metabolic syndrome and pituitary pars intermedia dysfunction), cardiovascular disease and dental disease. Reproductive hormones can also lead to a level of distraction (stallions and mares) or discomfort (mares), and make horses more expressive in their resistance behaviours.

Any comprehensive poor-performance evaluation relies heavily on a detailed history, including past performance records.

In this digital age, owners or riders often have many videos of the horse performing, sometimes over periods spanning several years. Although time-consuming, a detailed study of changes in the horse’s way of going can be extremely beneficial.

To obtain the most accurate history, it is often helpful to talk to as many of the people who have a significant input in the horse’s career and management as possible. These include (but are not limited to) the owner, rider, barn manager, trainer, farrier, physiotherapist, chiropractor, osteopath, saddle-fitter and massage therapist.

A comprehensive history is followed by a detailed physical examination including auscultation of the heart and lungs, palpation and manipulation of the limbs and back, trot-ups, flexion tests, examination on the lunge and under saddle, and a variety of exercise tests (depending on the sport and perceived problem).

Blood tests can be very important to rule out myopathies and subclinical liver and kidney disease, or mild inflammatory bowel conditions.

Further examinations may include endoscopy of the stomach and airways (both resting and during exercise), bronchoalveolar lavage, oral examination, electrocardiography at rest and exercise using telemetry, ophthalmic examination, objective gait analysis, diagnostic analgesia, radiography, ultrasound, scintigraphy, CT and MRI.

Finding a horse’s problems are, however, only half the battle. Determining which problems contribute to the poor performance is a whole other kettle of fish. In some cases, the only way to know whether a problem is contributing to the loss of performance is to treat it (for example, gastric ulcers). It is not uncommon for a horse to have multiple problems without a clear culprit.

In the rare case where no problem can be found, a bute trial can be helpful in resolving the relative contribution of behavioural problems, lack of ability and underlying discomfort.

Rider factors

Some riders simply have unrealistic expectations, which is particularly problematic where the rider or the horse’s ability is the significant limiting factor.

The author has on many occasions referred horses to trusted professional trainers to get an accurate view of a horse.

Rider skill can significantly influence a horse’s way of going and rider weight has a significant influence on lameness under saddle. A very unbalanced rider can make most horses look lame under saddle, while a highly competent rider can make a mildly lame horse look sound under saddle. It is important to bear this in mind when examining the horse.

Training and management considerations

Maintaining a healthy, happy sport horse relies on a balance of rest and exercise. Over and under-training are equally problematic. Each horse’s job, underlying issues, life stage and previous training must be taken into consideration when devising an optimal training programme. Many amateur horses don’t perform well because they are simply not fit and strong enough for what is being asked of them. Elite horses have exceedingly busy competition schedules that do not always allow for adequate recovery.

Both over and under-training will not only lead to poor performance, but predispose to injury. The author asks her riders to keep objective workload records of their exercise sessions for the horses in her care.

This allows her to balance their training (which is typically done in the school) and conditioning (done out hacking, on a water treadmill or on the gallops), and rest, for optimal performance.

The aim is to achieve maximal strength and fitness with minimal strain. Finding the right balance between strength, fitness and strain is the key to athletic longevity.

Having objective measures (for example, how many minutes of trot and canter per session, how many sessions of each type of exercise per week, what terrain or surface used in each session, and so forth) allows the author to tweak each horse’s training programme to improve performance. Many smartphone apps can be found on the market that track these parameters using GPS. Some also include heart rate data or even ECG analysis.

General husbandry and management, such as hygiene and nutrition, also play an important role.

Equipment considerations

Poorly fitting saddles, bridles, bits and nosebands will significantly increase musculoskeletal discomfort (Dyson, 2020).

Practitioners should have at least a rudimentary understanding of the fit and function of equipment used on sport horses.

To adequately dissect out the various contributing factors to a loss of performance, it is imperative that the veterinarian has a good grasp of the demands of each individual sport and becomes familiar with the early signs that something is amiss.