Page 111 - July 2019

Mineral balance is critical for musculoskeletal development of the growing foal, particularly of calcium-phosphorus and copper-zinc ratios.
EXERCISING THE GROWING FOAL
Exercise management is important for
the young, rapidly growing horse, and is best coupled with a balanced ration. Articular carti- lage of the joints needs normal use and weight bearing to optimize its development. Exercise is good for a growing foal, but keep in mind that excesses can lead to problems.
It is equally important not to impose limita- tions to exercise of a growing youngster since loading of the limbs promotes proper development of bone and soft tissue of the growing skeleton. Studies have shown that foals receiving controlled exercise as they grow have fewer joint injuries than horses not worked until they are two years old.
A study at Colorado State University looked
at six youngsters conditioned from birth until 18 months of age and compared them to six young- sters only given pasture turnout. Using computed tomography (CT scan) and histology (microscopic study) of the fetlock joints, the researchers discovered that the foals “exercised since near birth had fewer gross lesions in the joints, greater bone fraction in the dorsolateral (front outside) aspect of the condyle (rounded protuberance at the end of the bone), and higher bone formation rate compared to non- exercised horses.” Cartilage of joint surfaces responds favorably to appropriate location and duration of loading by producing extracellular matrix (proteo- glycans) that enhances the ability to successfully manage weight-bearing loads. The conclusion is that there is a net benefit of early exercise to young joints.
For foals at risk of DOD, complete restric- tion of exercise doesn’t guarantee complete prevention of DOD. However, avoiding exces- sive exercise strain is important to reduce joint trauma that can result in growth plate abnor- malities or formation of subchondral bone cysts.
Loading that occurs with normal weight bearing and light turnout exercise may promote acceptable cartilage development, particularly in the early months of foal growth. As the foal develops and ages, moderate exercise with grad- ual increases in intensity and duration results in better cartilage health and fewer injuries than that imposed by sudden, high intensity loading.
For the grown horse in training, good body weight and body condition score along with muscle strength are important goals.
For a young horse in training, find a middle ground of voluntary and controlled training.
Longeing and round pen work are commonly used training techniques early on but such circle work can be counterproductive to a healthy skeleton, especially if a young horse carries on without ap- propriate restraint. It’s probably better to hold off
on circle work until at least the yearling stage, or even longer. There’s evidence that articular cartilage responds in a ‘handed’ fashion – if a young horse works in one direction more than another, cartilage development can differ between limbs. Avoid repeti- tion in early exercise – repetition, such as incurred by constant circle work, is challenging not only to joints but to tendon, ligament and muscle, as well. Instead of attempting to use the round pen or longe line as a conditioning and training venue, just familiarize the young horse with short sessions of circle work.
For a young horse with early signs of DOD – joint and/or limb swelling, slight or overt lameness, limb angle deviation from normal and/or limb flexural deformity (‘contraction’) – exercise should be controlled, reduced or even stopped altogether and veterinary consultation sought promptly.
JOINT INJURY OF ALL AGES: THE IMPORTANCE OF A PROPER DIAGNOSIS
Prevention of injury is the primary objective to long-term joint health in all ages. For the grown horse in training, good body weight and body condition score along with muscle strength are important goals. Additionally, condition the horse for the specific exercise demands he is asked to perform. There is also great value in cross training, i.e. work the horse in a variety of athletic pursuits, such as trail riding, arena work, and cavalleti exer- cises. This is good not just for body development but also for a horse’s mental engagement.
In the event of an injury, rapid detection is important. Seek veterinary attention at first no- tice of abnormal clinical signs, such as swelling, heat, pain, and/or lameness. Joint effusion (excess fluid) is typically the first abnormal sign seen af- ter joint injury. In some cases, changes are subtle, as for instance a horse doesn’t perform up to
expectations. A steady decline in performance as- sociated with gait changes or a horse’s reluctance to perform expected athletic efforts is cause for concern. The earlier a joint insult is recognized and treated, the better the expected result.
It is sometimes tempting to ignore inconsis- tencies in a horse’s performance but continued exercise on even mildly injured tissue can create a long and frustrating course of disease progres- sion and treatment. Rather than trying to “work the horse through it,” stop exercise and contact your veterinarian for an evaluation. Local appli- cation of cold (water and/or ice) early after joint injury is helpful to stem inflammation. It’s best to withhold administration of NSAIDs (phen- ylbutazone, flunixin, firocoxib) until speaking with your veterinarian. NSAIDs are invaluable at decreasing inflammation, but their ability to mask pain can confuse examination findings.
To improve a horse’s athletic outcome, ac- curate assessment of joint injury is essential to de- velop an appropriate treatment plan. A thorough physical and lameness examination by your vet- erinarian helps narrow the concerns to a specific joint(s). Additional diagnostic tools further define the injury: regional anesthetic nerve blocks, joint fluid assessment, radiography, ultrasonography, nuclear scintigraphy and MRI. Returning joint anatomy and function to normal is the primary goal, and this relies on an accurate diagnosis and appropriate therapeutic regimen.
Articular cartilage of the joints needs normal use and weight bearing to optimize its development. Exercise is good for a growing foal, but keep in mind that excesses can lead to problems.
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VETERINARY VIEWS