What is PSSM in horses?

Tying Up is a muscle disease that causes painful muscle contractions. Symptoms include severe muscle pain and distress, apparent colic, excessive sweating, elevated heart and respiration rates, a stiff gait, muscle tremors and a reluctance to move. Milder forms may make the horse simply appear stiff, lazy or slightly lame.

There are various forms of tying up, with the two most common being Recurrent Exertional Rhabdonmyolysis (RER) and Polysaccharide Storage Myopathy (PSSM). The PSSM form commonly affects Warmbloods, Quarter Horses and draft breeds. Standardbreds can be affected by both forms of tying up.

The form of tying up a horse is affected by determines how it needs to be managed nutritionally.

What the horse needs for PSSM.

PSSM horses need a diet that is low in sugar and starch to reduce the amount of glucose available for storage as glycogen or other polysaccharides in the muscles. High energy fibres and fat should be used to provide the energy that would normally be provided by a grain based feed.