HoRse Feed & Supplements to Support Tying Up
What is Tying Up?
Tying up, or exertional rhabdomyolysis (ER), is an exercise-induced syndrome of muscle pain and cramping. Classic signs of ER include muscle pain and stiffness, excessive sweating, and reluctance to move. Researchers have uncovered several different causes for ER, including nutrition, over-exertion and genetics. The two main chronic forms are recurrent exertional rhabdomyolysis (RER) and equine polysaccharide storage myopathy (EPSM). Horses may experience single acute episodes of ER although they do not have the same muscle defects as RER or EPSM.
- RER is a potentially heritable disease affecting the regulation of calcium between cells that leads to the breakdown of muscle during exercise. Young horses in training, fillies, and horse with nervous temperaments appear to be most affected by RER.
- EPSM (also called PSSM) is most often seen in stock-type horses (Quarter Horses), Warmbloods (Hanoverians, Westphalians), and some draft breeds (Percherons, Belgians). It is the result of a defect in the storage of sugar in the muscles. Sugar stored in the muscle is known as glycogen. Normally, glycogen is broken down by an enzyme known as amylase and used as energy for performance. Horses with EPSM cannot break down the glycogen due to an abnormality making it resistant to breakdown by amylase. This results in the buildup of muscle glycogen and causes the horse to tie up. Symptoms include those associated with ER, but may include exercise intolerance, muscle stiffness, back pain, shifting lameness, muscle atrophy, and a camped-out stance.
Dietary Goals for EPSM or RER horses
Both hot and humid conditions and over-exertion can cause acute sporadic ER episodes. In the cases of dehydration, BUCKEYE™ Nutrition PERFORM ‘N WIN™, along with adequate water, can be used to replenish electrolytes lost in sweat.