Equine Polysaccharide Storage Myopathy (EPSM) is a glycogen storage disorder affecting skeletal muscle function.  Diets high in carbohydrates (starch) contribute to the onset of symptoms but do not cause the disease.

EPSM is primarily found in Warmblood, Draft Horses, Quarter Horses (including Paints and Appaloosas) and mixes of these breeds with other breeds.

In Quarter Horses there is a genetic correlation and inheritance is possible.  The incidence is not gender specific.

Horses with EPSM will always be more prone to muscle soreness.  The most common clinical signs are painful firm muscles (especially along the back and hindquarters), reluctance to collect and engage the hind end, stiffness, short stride, gait abnormalities, weakness, and muscle atrophy.  EPSM can progress to tying up (exertional rhabdomyolysis (ER), Monday Morning Disease) where there is severe muscle trembling and muscle damage that can lead to secondary kidney damage and even death.

Continue reading Tip of the Week – EPSM, EPM, IR, EMS, COPD, DJD, OA… Confused Yet? →