FEATURED HORSE ARTICLES
Lessons from the Farm
What we’ve learned can help you care for your horses and return the happiness they bring you.
Information from Our Horse Experts
Animal experts at the Purina Animal Nutrition Center share their knowledge about horses.
What is polysaccharide storage myopathy (PSSM) in horses?
PSSM is one of the causes of exertional rhabdomyolysis (ER), which is muscle damage from exercise, commonly known as tying up. An acute episode often begins within 20 minutes of light exercise and is characterized by reluctance to move, tucked-up abdomen, quivering in the flank, significant sweating and muscle stiffness. Horses affected with PSSM store 1.5 to 4 times the muscle glycogen as normal horses. Glycogen is a form of sugar called a polysaccharide, which is stored in the muscle to burn as fuel for work.