Tuesday, May 11, 2010

Exertional Myopathy in Endurance Horses Alina Vale, DVM Rood & Riddle Equine Hospital

www.alltechfeigames.com - Full Article

Endurance horses are pulled from competition for a variety of lameness and metabolic problems, and for occasional acute injuries that occur on the trail. Exertional myopathy (also known as “tying up”) is one of the most common metabolic syndromes in endurance horses. Other diseases that often require medical treatment include synchronous diaphragmatic flutter (commonly called “thumps” due to the characteristic flank movement caused by contraction of the diaphragm simultaneous with the heartbeat), colic (usually due to ileus which is a lack of gastrointestinal motility), choke (an esophageal obstruction) and “failure to recover” or heat exhaustion. Some severely compromised endurance horses will demonstrate a combination of these metabolic diseases at one time. This most often occurs when a horse is unfit or not yet ready for the level of competition.

Several of the listed disorders are caused by dehydration and subsequent poor perfusion, leading to decreased delivery of oxygen to body tissues especially muscle and the gastrointestinal tract. When a horse presents at the mandatory veterinary checkpoints, the veterinarian will assess specific parameters. These include: mentation (the horse’s behavior and alertness), heart rate, pulse quality (palpable under the jaw), mucous membrane color, capillary refill time (assessed by blanching the gums with a thumb and counting the time for return to the prior color), extremity temperature, and urine output. A horse that has poor perfusion will act dull or depressed, have an elevated heart rate (greater than 60 beats per minute), a pulse which is difficult to palpate, pale gums with a prolonged capillary refill time (greater than 2 seconds), cold limbs, ears and nose, and often has decreased or no urine production.

Horses suffering from exertional myopathy are identified and consequently pulled from competition based on the clinical signs noted above and hard and swollen muscles, especially involving the hind limbs and back. Many of these horses will have dark ‘coffee colored’ urine. Risk factors include inadequate training, a genetic predisposition, hot or humid weather conditions (causing excess sweat loss), high grain diets, viral infections, and electrolyte imbalances...

Read more here:

No comments: