Veterinary Care for the Sport Horse
By Erica Larson, News Editor • Nov 15, 2012 • Article #30869
Photo: Erica Larson, News Editor
From the start of his career to the end, an upper-level equine athlete is constantly exposed to stressors that could negatively impact his health, including strenuous exercise and long-distance travel. But starting even before you purchase your next sport horse, there are steps you can start taking to ensure he has a long and healthy career.
During the Nov. 1 sport horse symposium held in conjunction with the 2012 Alltech National Horse Show, Chris Newton, DVM, a partner and ambulatory practitioner at Rood & Riddle Equine Hospital in Lexington, Ky., presented about veterinary care for the modern equine athlete.
During his lecture, Newton discussed the prepurchase exam, how to develop a long-term fitness program, the importance of identifying injuries early, how and why to treat injuries for the long-term, and how we can extend the time until horses ultimately retire.
The Prepurchase Exam
"Doing a very investigative prepurchase exam is exquisitely important," Newton said. "Gathering information at that point in time is one of the best things you can do when you're purchasing a horse for competition."
Newton explained that his typical prepurchase exam takes two to three hours and is designed to, as he mentioned, gather as much information about the horse as possible. "You will miss more by not looking than by not knowing," he stressed.
His exams generally entail:
- Gathering a detailed history on the horse, preferably from more than one source;
- Carrying out a complete physical exam and documenting everything, even things that might seem superficial ("Small details can make big differences," he said);
- Evaluating the horse's movement in hand, under saddle, and under stress (i.e., pushing him a little harder);
- Obtaining a complete set of radiographs (which can be used to compare future X rays), paying careful attention to subclinical findings;
- Performing an endoscopic examination (this is especially important in Thoroughbred racehorses, he said, who might have already undergone surgery to correct laryngeal hemiplegia [roaring] by 3 or 4 years of age); and
- Running routine blood work (again, he noted blood work can be used to compare with future tests if nothing significant arises).
Throughout the exam, Newton will review his findings with the potential buyer but avoids making recommendations on whether or not his clients should purchase the animal.
"It's not my opinion whether they should buy the horse or not," he said. "It's my job to gather as much information as I can so if they choose to enter into this partnership, they're able to enter into it with their eyes wide open."
Even with a thorough prepurchase exam, it's impossible to know exactly what will be in a sport horse's future, he cautioned.
"People often ask, 'Is this horse really going to be a good horse?'" he relayed. "I tell them that the only two things I can really guarantee: He is going to go lame at some point when you own him, and he's going to die. Everything else is fairly unpredictable."
Conditioning for the Long-Term
After purchasing the horse, Newton said, it's time to start training and conditioning him for his new job. However he challenged owners to change the "paradigm" many hold about conditioning sport horses.
"Conditioning the horse is not just getting him cardiovascularly fit, which is the paradigm many of us consider it to be," Newton relayed. "Conditioning the horse is really building a foundation from this point to the point of reaching a successful athletic career, and then maintaining that career level."
To do that, he said, it's important to have an understanding of the different tissues and body systems that are affected by conditioning.
Neither the horse's airway nor his joint cartilage can "improve" with condition, he said, so it's crucial that we take care of what the horse has from the start.
"The airway is basically as healthy as it's going to be when horses are born," he said, so the main goal is to prevent the airway from being damaged. Improper stabling, dust and mold in hay, long distance transportation, and poorly ventilated trailers are just a few factors that could damage horses' airways and/or prompt inflammatory airway disease (IAD) development, a condition Newton likened to damage from smoking in humans. Ultimately, he said, IAD can lead to recurrent airway obstruction (heaves) and lung tissue fibrosis
"For every bit of lung function loss, we have the potential to diminish our performance," he stressed. Thus, taking every step to protect a performance horse's airway function is critical to top performance.
Hyalin joint cartilage is the other tissue that tends to only diminish from the time horses are born, he said.
"If I or (any other veterinarian) could come up with a method of healing joint cartilage in the lifetime of a horse ... we would be very wealthy people," he relayed. "But we haven't. So we have to realize that cartilage is precious. Extremely precious."
Newton said that cartilage is most commonly damaged when the joint's supporting structures aren't able to deal with the forces applied to the horse's limbs; this is often the case with poorly conformed horses. Therefore, good conformation is key when trying to prevent joint cartilage damage.
Fortunately, he relayed, most of the other tissues in the body are more reactive to training:
Cardiac muscles have a rapid response to training. It only takes six to eight weeks to maximize the heart's output.
"Bone really responds to training," Newton said. It's a tissue that's constantly changing, and its density increases where the greatest amount of pressure is applied and breaks down where the least amount of pressure is applied.
Muscle takes longer, but still moderately quickly, to respond, Newton said, but it does change with training.
Tendons and ligaments respond slower to training, Newton said, and it can take anywhere for "18 months to years" to properly adjust to training and conditioning. Strengthening tendons and ligaments need to be strengthened to properly protect the joint cartilage, he relayed, and the only way to strengthen them is to put the tissues under force via conditioning. These tissues also take the longest to heal from an injury, he said.
Hooves also respond quickly to training, as well, Newton said, however their response is generally more negative than positive as a result of the forces placed upon them during conditioning. Thus, a good farriery program is key to keeping a short horse's feet in good health.
For best conditioning results, Newton recommends taking incorporating both the trot and canter on a regular basis, as each gait develops a different set of tissues. The former is ideal to strengthen tendons and ligaments and should be used for a long time in the beginning stages of conditioning, he said, while the latter is more effective at building muscle.
Finally, Newton touched on the nervous system, which is the tissue that takes the longest--years, he said--to develop.
"A lot of what we do with our horses every single day is developing the nervous system," he said, noting that it's also one of the most important tissues to develop.
"The horse that doesn't put up all the malarkey, who doesn't leap around; the one that goes forward when he's asked, that moves laterally for each step he's asked to, is the horse who's least likely to injure himself," Newton relayed.
Essentially, he said, there are fewer demands on a horse's body when his nervous system is fit.
Once the rider or trainer has developed a dynamic conditioning program that can change as horses' continually develop, Newton said, it's important to work to identify injuries in the subclinical state before they develop into clinical problems.
Identifying and Managing Subclinical Injuries
Newton said that through advances in veterinary technology and diagnostic exams, it's now possible to identify problems prior to them beginning. That said, he relayed, "it's very difficult for me to detect subtle problems if I've never seen the horse before. In order for your veterinarian to become an effective member of the team that trains the horse, you've got to allow them to feel the horse on a more recurrent schedule."
Thus, the first step to identifying subclinical problems in horses is allowing the veterinarian to evaluate the horse intermittently throughout the year regardless of the animal's performance level.
Newton said he uses the baseline information obtained during the prepurchase examination to help identify subtle changes in horses' bodies--be they radiographic, lameness-related, or otherwise--when an owner calls and says their horse "just doesn't feel right."
Newton discussed the different clinical tools used to diagnose sub-clinical problems, including lameness examinations, palpation, observation, digital radiography, ultrasonography, bone scans, thermography, and magnetic resonance imaging.
Once a subclinical problem has been identified, the goal is to manage the issue before altering the conditioning program to keep the acute injury from becoming chronic. Should the injury progress into a chronic state, the goal then becomes to manage the chronic inflammation, Newton said.
Common causes of sub-clinical and clinical lameness in sport horses, he said, include:
- Fetlock arthritis (a significant cause of reduced career length, he said);
- Hock arthritis (which is a less significant cause of reduced career length);
- Knee arthritis (rarely found in sport horses, he said);
- Stifle arthritis (which has a tendency to nag at athletic horses, he said);
- Bowed tendons (which are very common in sport horses and take roughly 12 months and careful rehabilitation to heal properly; he also noted that about 80% of horses aren't unsound when the bow occurs); and
- Suspensory ligament problems (painful injuries which can easily become chronic, Newton said).
Treatment options for each injury will be specific to the situation, Newton said, but common management options include:
- Systemic anti-inflammatories (including dexamethasone, phenylbutazone, firocoxib, and polysulfated glycosaminoglycan, among others);
- Topical anti-inflammatories (including ice, poultice, sweats, diclofenac cream, and dimethyl sulfoxide, among others);
- Intra-articular injections (including steroids and hyaluronic acid);
- Interleukin-1 receptor antagonist protein, commonly known as IRAP;
- Shock wave therapy;
- Rehabilitation techniques (including ultrasound therapy, swimming, electric stimulation, massage therapy, magnetic therapy, laser treatment, and focused exercise); and
- Surgery (which, Newton said, can be effective, but it also requires rehabilitation to be successful).
Post -treatment, the horse will either return to being sound, or he'll end up functionally sound, functionally lame, or lame. The good news, Newton said, is that he's seen several functionally lame horses continue on in successful careers.
The ultimate goal, from the prepurchase exam through the career, is to extend the time to retirement, Newton said. To accomplish this, he said, conduct a thorough prepurchase examination, use a team approach--including the veterinarian--when conditioning a horse for his career, identify problems before they become clinical, and make use of modern medicine when problems do arise.