Equine Metabolic Syndrome (Peripheral Cushings)

  by Robert N. Oglesby DVM

Obesity has become the most common nutritional disease in horses in the prosperous developed parts of the world. Declining work loads in combination with improved feeds and forages that are affordable have led to this situation and horses are not adapting to it very well. Horses were designed to take advantage of the good times with efficient storage of energy that would then get them through the lean times of the year when forage became scarce. The problem now is that there are no longer any lean times. The horse continues to store more fat. Both human and veterinary medicine are beginning to understand how obesity effects endocrine and metabolic processes that predispose to disease. In both humans and horses insulin resistance is the major event and in horses the main disease problem becomes founder (laminitis).

In the past this deranged metabolism has been labeled as Hypothyroidsim, Peripheral Cushings Disease and most recently Equine Metabolic Syndrome (EMS). Since there is neither impaired thyroid function nor primary cortisol elevation, which defines endogenous Cushings, Equine Metabolic Syndrome best fits. This article discusses the physiological events in Equine Metabolic Syndrome and what might be done to treat and prevent this increasingly common problem.