Equine Metabolic Syndrome and the Easy Keeper

If your horse gains weight eating air, founders on grass every spring, and has a cresty neck, he could be insulin resistant. Insulin resistance is part of an equine health issue called Equine Metabolic Syndrome (EMS).

Equine Metabolic Syndrome is defined as a condition of: 1) obesity and/or patchy fat accumulation, 2) insulin resistance, and 3) chronic laminitis in middle-aged horses (8- to 18-years-old).

Although there is a strong genetic component to EMS, obesity is the primary problem setting off the cascade of metabolic abnormalities.

Breeds especially prone to EMS include:

  • Morgans;
  • Saddlebreds;
  • Paso Finos;
  • Peruvian Pasos;
  • domesticated Spanish Mustangs;
  • certain warmblood lines;
  • some pony breeds.

The theory is that certain breeds have a "thrifty gene" when it comes to metabolizing their food, and have learned to get by on very few calories. Now that we bring them into enclosed areas and feed them grains (especially sweet feed) without requiring much work, those thrifty genes cause fat to be stored in unusual locations.

This particular fat has a large blood supply and is very active, producing its own hormones that serve to cause more fat to be stored, creating a vicious cycle.

Horses are diagnosed with EMS through physical appearance, routine blood tests, and specific insulin and glucose tests. The treatment is simple but not easy: reverse the obesity.

Getting a horse to lose weight requires a three-pronged approach:

  • Increase exercise--under veterinary guidance if the horse is already laminitic;
  • Feed a strict diet--hay, not pasture; multi-vitamins and minerals, not grain;
  • Supplement as necessary--reduce oxidative stress with antioxidants like Vitamin E.

See www.TheHorse.com/ViewArticle.aspx?ID=9476 to read Dr. Gray's recommendations for managing "hard keepers."


This is a summary of Dr. Gray's presentation on managing the hard keeper, discussed at Equine Affaire Ohio. Dr. Gray's GetSmart discussions at the SmartPak Store in Natick, Mass., will continue next fall. For more information see www.smartpakequine.com/store.aspx.  

About the Author

Lydia Gray, DVM, MA

Lydia Gray, DVM, is Medical Director and Staff Veterinarian for SmartPak Equine. She was previously the executive director of the Hooved Animal Humane Society in Woodstock, IL, and an Owner Education Director for the American Association of Equine Practitioners.

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