Tying-Up in Quarter Horses and Thoroughbreds: Separate Diseases with Common Clinical Signs

Although horses share similar clinical signs of acute rhabdomyolysis, numerous etiologies exist for tying-up. In Quarter Horses tying-up is often caused by a heritable glycogen-storage disorder called polysaccharide storage myopathy that can be managed by a fat-supplemented, hay-based diet, and regular daily exercise. In Thoroughbreds recurrent exertional rhabdomyolysis (RER) is often due to a heritable disorder of muscle contractility that is intermittently expressed during stress and excitement. RER is best managed by decreasing excitement and nervousness in combination with a diet designed to meet but not exceed caloric requirements. Authors’ address: Depts. of Clinical and Population Sciences and Veterinary PathoBiology, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108. r 1999 AAEP.