Equine Metabolic Syndrome Versus Cushing's Syndrome

Fresh from the AAEP Annual Convention, here's an update on what we know about these two disorders and how to manage them:

Equine metabolic syndrome typically affects horses aged 8 to 18-years-old. Pony breeds, domesticated Spanish Mustangs, Peruvian Pasos, Paso Finos, and some Warmblood breeds appear especially prone. A preliminary diagnosis is based on obesity, insulin resistance and insidious onset of laminitis. EMS horses typically have fat deposits in the crest of the neck, over the tail head, above the eyes, behind the shoulders, and in the sheath of male horses. Diagnosis is confirmed by measuring insulin and glucose levels in the blood. Unfortunately, there are no medications to treat EMS. At this time, experts recommend a low sugar/starch diet, exercise, and antioxidants such as Vitamin E to help manage the oxidative stress that comes with the syndrome.

Signs of equine Cushing's syndrome typically first appear in horses aged 18 to 23-years-old and include: hirsutism (long curly hair), weight loss and muscle atrophy, depression and poor performance, normal to increased appetite, laminitis, and fat deposits as described above. The best tests for Cushing's are the dexamethasone suppression test and the ACTH stimulation test. And while the disease cannot be cured, pergolide seems to help manage the disease better than cyproheptadine. Because some horses with Cushing's develop insulin resistance, they should also be fed a low sugar/starch diet, although some might need additional calories from fat. Antioxidants might be useful in this syndrome as well.


This is a summary of Dr. Gray's presentation on equine metabolic syndrome and Cushing's, part of the SmartPak GetSmart series.

GetSmart discussions with Gray will continue March 14 with "Spring Ahead: Management strategies to get your horse ready for the new season," and April 25, with "Joint Supplements: What's hip and what's hype?" Discussions are hosted at the SmartPak Store in Natick, Mass. 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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