Equine Metabolic Syndrome (EMS) is an endocrine disorder in obese horses that is commonly associated with insulin resistance (IR), laminitis, and fat redistribution.  EMS is more often diagnosed in middle-aged horses, but can occur in younger horses as well.


Genetic Predispositions

Studies have shown that certain breeds are predisposed to having IR and EMS.  Those breeds include:

  • Saddlebreds
  • Tennessee Walking Horses
  • Morgans
  • Paso Finos
  • Quarter Horses
  • ponies

These breeds tend to be “easy keepers”, requiring fewer calories to maintain body weight or become obese.  Ponies in particular have the highest prevalence of IR.


Clinical Presentation

Clinical signs of EMS include:

  • Obesity and fat redistribution around the tailhead, neck, prepuce, mammary gland, shoulder area, and around the eyes
  • Presentation of a “cresty neck”
  • Mares may have a history of infertility
  • Unlike with Cushing’s disease, horses with EMS have a normal hair coat and shedding pattern
  • Laminitis

Laminitis and a “cresty neck” are the two most common complaints horse owners describe.


Fat redistribution around the tailhead.
Fat redistribution around the tailhead.
"Cresty neck"
“Cresty neck”


What causes laminitis to occur?

Insulin resistance is the result of a lack of insulin receptors or an inappropriate receptor response.  IR leads to a decrease in glucose uptake and hyperglycemia (an excess of glucose in the bloodstream), vascular dysfunction and inflammation, vasoconstriction, and increased vascular resistance.  Laminitis is thought to result from decreased glucose uptake, vascular dysfunction and inflammation, and a decrease in blood flow to the lamina in the hoof, all of which can be caused by IR.


How is Equine Metabolic Syndrome diagnosed?

Your veterinarian will diagnose EMS based on your horse’s clinic history, clinical signs, and by ruling out other conditions associated with hyperglycemia and laminitis.  Blood work is often performed to determine the insulin, leptin, and glucose levels.


How is Equine Metabolic Syndrome managed?

Diet: The basis for feeding horses with metabolic disease is low starch and higher fats.

Grain: Several commercially produced feeds are available, including SafeChoice Special care and Purina Wellsolve L/S.  These should only be used to supplement calories needed to maintain an appropriate body condition.

Forage: Lower quality hay is best. Sugar-rich grasses should be avoided.  This is worst with new grasses in the springtime.  Turnout should also be avoided later in the afternoon or at dusk as this is when grasses are more sugar-rich. Grazing muzzles can be worn to slow down forage intake.

Exercise: For horses not currently experiencing a bout of laminitis, a regular exercise program should be used to encourage appropriate body condition.  Please consult with your veterinarian on the appropriate regimen for your horse.

Regular veterinary visits are recommended to identify subtle or early progressive signs of disease.

Initially, bloodwork should be checked frequently. Once your horse’s EMS is more controlled, bloodwork should be rechecked at least yearly to confirm that your horse is still being appropriately managed on their medication.

Although there is not a specific treatment for EMS, there are several medications and supplements available that can help with increased metabolism and reduce insulin sensitivity, such as Thyro-L and Metabarol.

Platinum Performance carries a variety of oral supplements for metabolism support: