What could be behind a horse’s failure to develop or maintain fitness as expected? Andrea Oakes investigates
YOU prepared him methodically for the season, but your horse’s energy reserves seem unusually low. Or perhaps his fitness levels are not progressing, despite the fact that you’re following a training programme.
Before delving too deeply into the potential veterinary issues, performance horse consultant Peter “Spike” Milligan MRCVS advises first placing your training techniques under the microscope. Only then can a horse’s fitness – or lack of it – be objectively assessed.
“A competition horse needs to be just fit enough,” says Spike, a British Eventing youth performance squad vet. “Event horses at the lower levels are often too fit, which can compromise their soundness, appetite and condition, as well as their ability to achieve a good dressage score. Yet a slightly overweight, underfit eventer is at risk of injury.
“A good starting point is to understand the athletic demands at your horse’s level,” adds Spike. “You can then set measurable fitness parameters.”
To benchmark fitness levels, Spike suggests using a stopwatch and a horse heart-rate monitor.
“You can then assess fitness by speed of recovery, recording the time taken after a work period for the horse’s respiratory rate to return to 16 breaths per minute – or for his nostrils to stop flaring. If you do two six-furlong gallops, for example, the trend should be for the recovery time to shorten.
“Bear in mind that genetics play a part in a horse’s fitness capacity,” adds Spike. “A horse with more thoroughbred in his breeding will have greater innate fitness and an ability to maintain this. A warmblood, however, may have more power and endurance but less speed.
“Age also matters,” he adds. “The equine cardiorespiratory system is incredibly efficient; young Flat racing horses are on the track at two to three years, but they are still maturing skeletally. While older competition horses may be more at risk of developing an injury that rules out work, they tend to retain a natural degree of fitness. Their riders often know them well and know how to bring them to the required level. It’s all about understanding the horse you have.”
Using a heart rate monitor
While a phone app can tell you how fast a horse is moving, a heart rate monitor will tell you how hard he is working.
“A horse’s heart rate must rise above 180 beats per minute to reach the anaerobic zone,” says Spike. “He needs to work, otherwise you’re not achieving much.
“To push your horse’s heart rate up, you need to go further, faster or steeper. If you go steady, you’ll need to go that much further. The trick is to find the balance, maximising the effect of his training without undue wear and tear or increased injury risk.
“You may need to train a horse to gallop, as some warmbloods will only do a fast canter and never really raise their heart rate. But be careful that a buzzier thoroughbred type does not lull you into a false sense of security – he may be fine for up to six or seven minutes at his first long-format event, but he’ll run out of steam if you’ve not primed his anaerobic pathway and his body is not ready.”
Missing a beat
PROVIDED a training programme is progressive, is tailored to the individual and incorporates rest days, fitness should follow. If a horse remains under par, the areas examined first are usually the heart and lungs.
“While equine heart disease is relatively uncommon, we would check for a correct rhythm, with no murmurs, using a stethoscope on the horse at rest,” says Spike. “The most typical issue is atrial fibrillation, although horses with this irregular or abnormally fast heart rate tend to present with marked exercise intolerance and tire very quickly.
“The next step is to perform an electrocardiogram [ECG], in the stable or while the horse is ridden, to further examine the heart rhythm and electrical activity,” adds Spike. “A specialist can run a heart scan – an echocardiogram – to assess the structure of the heart.
“An irregular beat can occur when the heart enlarges. This is sometimes due to a problem, such as a leaky valve, but is also seen in very athletic horses with a bigger heart. Famously National Hunt horses Denman and Sprinter Sacre both suffered atrial fibrillation during their careers. This condition sometimes corrects itself, or may require medical treatment or even electrical cardioversion, where the horse’s heart is shocked back into normal rhythm under general anaesthesia.”
Lung and respiratory health is also key to performance.
“Low-grade inflammation in the lungs can be limiting,” explains Spike, referring to airway disease caused by challenges in a horse’s breathing environment. “This can be assessed with blood samples, or by sampling mucus in the lungs after exercise.
“Airway health tends to be under-appreciated,” he adds. “While minor airway issues can be managed with medication and treatment, it is vital to maintain a clean environment for the competition horse.
“Use only good-quality bedding and forage, and aim to reduce the respirable particles and chemical irritants a horse can breathe in, such as dust, cobwebs and ammonia. Vaccinating all yard horses against the equine herpes virus will also contribute to respiratory health.
“There may be a limitation in the airway that prevents air from entering and exiting the lungs correctly,” continues Spike, explaining that horses with these issues were previously termed roarers or whistlers.
“If noise is heard and considered a potential problem, your vet may recommend an endoscopy to examine the larynx and the back of the throat. This can be performed in the stable, but may be more revealing during exercise – termed an overground endoscopy.”
“POOR performance is often due to orthopaedic problems, so a thorough lameness evaluation is an essential part of the process,” says Spike. “Blood testing can also reveal post-viral conditions that can lead to low white blood cell counts and anaemia.
“Check you’re feeding the right fuel,” he adds. “Different disciplines have specific requirements. An event horse needs a tailored diet for endurance, incorporating more oil and fibre, whereas those in dressage or showjumping need more heating food for quicker power.
“Ensure a constant supply of drinking water and consider feeding electrolytes for healthy muscle function. These should not be necessary every day, unless a horse is sweating hard.
“Diet is also linked to muscle function,” says Spike, explaining that muscle problems can lead to exercise intolerance.
“The condition exertional rhabdomyolysis, known as tying up, is seen in its most extreme form as acute muscle cramp, but can occur as more subtle but nevertheless performance-limiting muscle damage. Blood samples and muscle biopsies can reveal more. While close observation of muscle enzymes is key in racing, problems can be limiting at all levels with the competition horse, depending upon the individual.”
More in-depth diagnostics, such as blood lactate testing, are available but seldom necessary.
“The answers are usually to be found closer to home,” says Spike. “It is rare for a horse’s fitness levels not to improve with a planned, varied and progressive exercise programme that, ideally, is easily measurable.”
This exclusive veterinary feature is also available to read in Thursday 8 July’s Horse & Hound magazine
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