MAY 1997 BACK ISSUE

Part of Horse Previews Magazine website. 11/6/97.

Equine Tying Up Disease

News from MORRIS ANIMAL FOUNDATION
45 Inverness Drive East, Englewood, Co 80112 * 303/790-2345
Dr. John F. Cummings Memorial Study:

New diet proposed for horses

We all know what Monday morning blues can feel like to a human, but did you know there is a disorder called "Monday Morning Disease" or "tying up" that can affect many breeds of horses? The disorder is called equine rhabdomyolysis and it can be fatal. The problem starts when the horse's body accumulates too much glycogen, a by-product of carbohydrate metabolism, within the skeletal muscles. As glycogen builds up in the muscle fibers, the horse loses strength and the muscles begin to degenerate following exercise. The horse weakens and typically lies down to relieve its discomfort. In many cases, the horse cannot rise to eat or drink, and eventually dies.
A Morris Animal Foundation-sponsored study is addressing the physiological differences that cause a horse to "tie up" and determining an effective treatment plan. This investigation is being conducted at Cornell University College of Veterinary Medicine under the direction of Beth A. Valentine, DVM, PhD. This study, entitled "Equine Polysaccharide Storage Myopathy: Biochemical Studies and Effect of a High Fat Diet," is investigating the abnormal muscle and enzyme level differences between healthy horses and affected horses.
"The presence of an abnormal amount of glycogen in the muscle tissue, and the involvement of muscle fibers that specifically use glycogen for energy, has led to the hypothesis that this disorder is due to a defect in the glycogen metabolic pathway of affected horses," according to Dr. Valentine. This means the affected horses cannot use carbohydrates correctly for energy production. The investigative team is evaluating the effects of a low carbohydrate, high-fat diet on this metabolic problem in affected horses.
This study is in the early stages, but according to Dr. Valentine the diet will not have negative effects on any horse, and may be able to help affected horses perform more normally, even if the diet does not improve the glycogen accumulation problem.
After examining the affects of this diet on many horses over a period of time, the investigators plan to determine if the diet alone is causing an improvement in affected horses.
Horse lovers anxiously await the results that will be obtained from this one-year Morris Animal Foundation-funded project.