Q: I have a 16-year-old jumper that has been diagnosed with EMS. How can I feed him to support his somewhat heavy workload without worsening his EMS?

A: Equine metabolic syndrome (EMS) is a metabolic disorder characterized by insulin dysregulation, which significantly increases a horse’s risk of developing endocrinopathic laminitis. Carefully managing your horse’s diet will help control EMS and protect his long-term health.

Horses with EMS often produce an exaggerated insulin response after eating feeds high in sugars and starches, known as nonstructural carbohydrates (NSCs). For that reason, managing NSC intake from both forage and concentrates becomes central to the diet.

Choosing a Forage for Your EMS Horse

Currently nutritionists recommend feeding EMS horses hay containing no more than 10% NSCs on a dry matter basis.

To find the NSC content of your hay, you can collect a sample with a hay corer and submit it for laboratory analysis. Many local agriculture extension offices or feed stores have this equipment available for loan. Alternatively, a qualified equine nutritionist or equine extension specialist can help you collect and submit a sample for testing.

When selecting low-NSC hay to manage your EMS horse, remember that lower NSC levels do not always mean the forage is low in digestible energy. This distinction is particularly important for horses in moderate to heavy workloads. If your hay is more calorie-dense hay, such as alfalfa, you might be able to reduce the concentrates in his diet. First consider the nutritional profile of your forage when building a ration because it determines what nutrient gaps you will need to fill with a concentrate or ration balancer.

Concentrates for Performance Horses With EMS

In recent years researchers have clarified recommendations for feeding concentrates to horses with EMS. If you need to feed a concentrate, researchers suggest limiting a horse’s NSC intake to less than 0.1 grams per kilogram of body weight per meal. You can calculate the safe amount for your horse using his body weight, the NSC content of the feed, and the amount fed at each meal. Exceeding this threshold can trigger an exaggerated insulin response, particularly in horses with EMS.

Because horses like yours in regular work might need additional calories beyond what forage provides, increasing the number of concentrate meals per day can help keep each feeding within this recommended NSC limit.

Another strategy for adding calories relies on fat rather than carbohydrates. Energy-dense fat sources such as oils can increase caloric intake without triggering the insulin response seen with higher-carbohydrate feeds.

Take-Home Message

Feeding an EMS horse in regular work should begin with a forage low in NSC that provides sufficient digestible energy. Carefully manage his concentrate intake (including performance feeds or ration balancers) so each meal stays below the recommended threshold of 0.1 grams of NSC per kilogram of body weight. If he needs additional calories to support his workload, first consider higher-fat feeds or supplemental oils for a safer option to provide energy without increasing his insulin response.