MUSCLE DISORDERS: UNTYING THE KNOTS THROUGH NUTRITION

Some unfortunate horses develop stiffness, painful muscle contractures, profuse sweating, and elevated respiratory rates during or following exercise. The term “tying-up ” is used to describe horses with these clinical signs. In severe cases, horses may be unable to move their hindquarters after exercise, and muscle breakdown results in dark urine due to the release of myoglobin. Horses may be so painful with tying-up that they will paw and roll resembling colic. Other terms for this syndrome include azoturia, Monday morning disease, exertional rhabdomyolysis, and chronic intermittent rhabdomyolysis. It has been implied or assumed that there is one underlying cause for tying-up in horses. In 1917, Dr. Steffin commented on tying-up, saying “no one disease in the horse has been subject to so many theories and hypothetical suggestions as this one. ” This statement remains true. Veterinarians and owners have noted improvement in their horses’ signs of tying-up with various new diets or supplements. The variable response of horses to these treatments has fueled the controversy regarding tying-up and its actual basis. In this article, we provide a brief review of the history of tying-u