This veterinarian explains why a “whole horse” approach to veterinary management works best.

I’m often asked, “Why isn’t my horse performing like he used to?”

Maybe your horse has suddenly started to kick out behind when you ask for a lead change. Maybe he’s acquired a new right-to-left drift over a fence, or maybe he just seems irritable and less eager to go forward under saddle.

Whatever the complaint, it could be that you’re seeing veterinary causes of poor performance. Poor performance or a deterioration in performance is a common, and very appropriate, reason to call your veterinarian for an appointment. Identifying the cause or causes of your horse’s poor performance will most likely require a thorough and sometimes time-consuming examination by your veterinarian that might not necessarily resolve the situation in one visit.

It’s incredibly important that the veterinarian evaluating the horse has extensive knowledge of the discipline and level in which that horse is competing. There are more prevalent causes of poor performance within each discipline. For example, respiratory lower airway disease may be a much more limiting factor in an endurance or three-day event horse than in a cutting or western performance horse. A sports medicine veterinarian who’s used to working with upper-level dressage horses may be more able to see and block the subtle gait asymmetry that may be limiting the horse in his left canter pirouettes.

Each discipline places unique demands on our equine athletes, so therefore the most limiting causes of poor performance can vary with these demands. In addition, the discipline and level of the horse has to be taken into consideration after the diagnosis is made and when coming up with a therapy and rehabilitation plan. For example, you might be able to follow and maintain a low grade suspensory branch desmitis during an upper-level dressage horse’s season, but the same condition may be a season-ender due to the gallops and conditioning required and the risk of career ending injury in a four-star event horse.

When attempting to come up with a diagnosis, it can be helpful to break the causes of poor performance down into three main categories: 1) musculoskeletal causes; 2) internal medicine causes; and 3) extrinsic causes. Also, we need to bear in mind that a horse can often have more than one cause of the poor performance at a particular time.

Musculoskeletal Issues

Musculoskeletal causes would include orthopedic and soft tissue issues that may or may not result in lameness. For example, neck and back pain can commonly cause poor performance, however the horse may not display signs of overt lameness. This is why both a thorough clinical examination, including palpation of the neck and back and detection of areas of underdeveloped muscles, and a moving examination are necessary.

Many musculoskeletal causes are only detectable or are exacerbated under tack or in work. An under tack or “in work” examination is a critical part of the poor performance musculoskeletal examination. It can be necessary to block, or perform diagnostic analgesia, on the horse under tack so a subtle or inconsistent lameness can be further localized.

Other common musculoskeletal causes may include things like subchondral bone pain, tendonitis and bilateral hind proximal suspensory desmitis. Sometimes musculoskeletal issues can be subclinical or very difficult to diagnose without the addition of advanced imaging such as nuclear scintigraphy (bone scan) or magnetic resonance imaging (MRI).

To make things more challenging, lameness and good performance are not necessarily exclusive. Many experienced upper-level sport horses perform well and at top levels with low grade manageable musculoskeletal issues. For example a Grand Prix dressage horse may be able to perform with some low level fetlock discomfort, however it only starts to affect his performance when he develops additional back pain from a poor fitting saddle. This is where a complete examination and a “whole horse” approach is critical to getting to the real source of the performance problem.

Internal And Extrinsic Issues

Internal causes would include issues with the neurologic system, the gastrointestinal system, cardiovascular system, respiratory system or systemic illness. Equine gastric ulcer syndrome and inflammatory lower airway disease are two common causes of equine poor performance in this group. Additionally, the early onset of equine protozoal myeloencephalitis can make a horse have low grade weakness or ataxia that may make him only feel less forward or less eager to do his job to the rider.

Oftentimes the diagnosis of these causes can require additional laboratory testing or a consultation from an expert in a particular field. Veterinarians can’t be experts in all fields, and it’s important to work with one who is eager and willing to consult with additional experts when necessary. In a case of getting to the bottom of poor performance in a sport horse, everyone must be on the same team!

Extrinsic causes of poor performance can include things like inadequate nutrition, inadequate fitness of the horse for the task, poorly fitting or inappropriate tack, or lack of capacity or talent of the horse or rider.

These things may only be able to be diagnosed after a thorough veterinary examination to exclude other causes. It may even take additional input or a consultation with an expert specialized in another realm of veterinary medicine such as a cardiologist or a nutritionist.

The Exam: What To Expect

A veterinary examination for poor performance in a sport horse could vary depending on the presenting complaint. However, almost all of these exams would include 1) a thorough history from the client or rider; 2) a detailed clinical examination including observation and palpation, listening to the heart and lungs, possibly an ophthalmic examination; and 3) an extensive musculoskeletal exam including flexions, exam on a longe line, and probably most importantly examination under tack.

The under tack examination is one of the most critical parts of the poor performance examination. This allows the veterinarian to see the sport horse doing its job, hopefully on appropriate footing, at an appropriate level, under the normal rider and in the horse’s normal tack. This sometimes requires prior communication to make sure there is a suitable surface to ride on and that the rider is available.

One can see that the cause of a forelimb lameness on the longe line on asphalt might not be the same cause of poor performance in arena footing under tack. Both issues probably warrant investigation, however the rider won’t be pleased until after the second cause is addressed.

After the completion of those three things, then the veterinarian will determine which additional tests or diagnostics need to be performed to gain the greatest amount of information and insight. For example, if the horse shows a subtle gait asymmetry only in lateral work under tack then maybe the veterinarian will elect to do diagnostic nerve or joint blocks while the horse is being ridden to localize the pain. Additionally, if there are some low grade abnormal lung sounds picked up at rest, and the horse makes an increased respiratory noise at the gallop then maybe the veterinarian will elect to do additional respiratory testing such as a dynamic endoscopy examination.

The poor performance evaluation can be a fantastic way to detect injuries early on. It encourages us as riders, horsemen and veterinarians to pay attention to more subtle clinical findings and potentially detect a low grade injury before it becomes a more serious season or career ending injury.

For example, maybe a horse that is always clean and tight legged all of a sudden begins to show fill and slight heat in a front fetlock. The horse may not be lame yet. He may just show a positive response to fetlock flexion, increased fill, low grade heat, and may not work as well under tack. If an investigation is performed early, an ultrasound is performed, and then potentially a very mild suspensory branch injury is detected. The horse is put in an appropriate treatment and rehabilitation program, and the problem is resolved in 90 days. This is in contrast to waiting until the horse is grade 2/5 lame and has a central core lesion in the suspensory branch that will take injection of regenerative therapies and 12-18 months of rehabilitation. Early detection of things like this takes a team of people who know their horses well and pay attention to more subtle changes.

The poor performance examination also allows for more proactive management of the equine athlete to prevent potential reoccurrence of the same issues. If a horse is extraordinarily predisposed to back pain relative to saddle fit, then several appointments can be made proactively throughout the course of the season to address the saddle fit as the topline changes with conditioning and fitness. If an event horse is predisposed to inflammatory lower airway disease then certain critical management changes can be instituted both in the day-to-day barn activities and during shipment, such as steaming or soaking the hay, making sure the horse is out of the barn during mucking, and choosing appropriate low dust bedding and forage.

Poor performance examination of the sport horse can be time consuming but incredibly rewarding for the client and the veterinarian. It can allow for detection of early injury and can give insight into more proactive management of the horse for better health. There are a multitude of causes of poor performance, and sometimes the cause is multifactorial. A knowledgeable veterinarian who is willing to perform a thorough methodical examination can many times come up with the cause and the proposed solution to make for a much happier horse and a much better performance.

After 15 years of equine practice in Virginia and Florida, Dr. Christiana Ober relocated to Wiltshire, England, in 2015. She and her husband, Dr. Andre Buthe, who is the team veterinarian for British Dressage, jointly have an equine sports medicine practice there. She specializes in sports medicine, diagnostic imaging, lameness and the pre-purchase exam. After 10 years of assisting the Canadian eventing team, Dr. Ober is now the team veterinarian for the New Zealand eventing team. She graduated from the Virginia-Maryland Regional College of Veterinary Medicine in 2000.