Horses with equine metabolic syndrome (EMS) struggle to metabolize sugars due to reduced insulin sensitivity, often leading to obesity and an increased risk of hyperinsulinemia-associated laminitis. To mitigate this risk, feeding programs for EMS horses should aim to reduce body weight and minimize insulin spikes while ensuring adequate intake of protein, vitamins, and minerals.

Dietary Guidelines

For EMS horses in Ireland and the Northern Hemisphere, a forage-based diet complemented by a ration balancer or vitamin and mineral supplement is recommended. Pasture access should be restricted, especially in spring and early summer when grasses accumulate high levels of sugars and fructans, which can trigger insulin spikes.

If pasture turnout is allowed, it’s best to limit grazing to early mornings, bringing horses in by 10:00 a.m. Nonstructural carbohydrates (NSCs)—which include sugars, fructans, and starch—build up in plants during the day. After cool nights, NSC levels are already high in the morning and increase throughout the day, making it important to manage grazing times carefully. Grazing muzzles can help reduce intake, but turning out in a drylot with forage is the safest option.

Forage Choices

Mature hay with an NSC content below 10% on a dry matter basis is ideal for EMS horses. In Ireland, common hays like timothy or meadow hay are suitable choices. The maturity of the hay at harvest influences NSC levels, with mature, coarser hay generally being lower in NSCs than softer, leafier hay.

Testing hay for NSC content is recommended, and if low-NSC forage isn’t available, soaking hay can reduce its sugar content, though results may vary. Another alternative is to substitute some high-NSC forage with a guaranteed low-NSC product like a hay replacer.

Vitamins, Minerals, and Energy Needs

Forage-based diets often lack sufficient vitamins and minerals, particularly trace minerals. Concentrated vitamin and mineral products or ration balancers such as Stamm 30 are recommended to meet these needs, especially for overweight horses with low energy requirements, as they provide essential nutrients without increasing feed intake significantly.

Not all EMS horses are obese; some may need additional energy for exercise or weight maintenance. In such cases, avoid grains like oats, corn, and barley, which have a high glycemic index and can spike insulin. Instead, consider low-glycemic ingredients like soaked beet pulp or rice bran or fully balanced low starch products such as Re-Lite, Re-Leve or Re-Solve. Fat sources such as soybean or canola oil, and stabilized rice bran, can also safely increase energy intake without causing significant insulin responses.

Protein Considerations

Ensuring adequate but not excessive protein is crucial. Ration balancers, even those with variable protein content, have been shown not to significantly affect insulin response, making them suitable for EMS horses. For those not needing weight loss, adding a small amount of alfalfa hay can boost protein intake without significantly increasing NSC levels, though it should be avoided if weight loss is the goal due to its higher energy content.

Managing the diet of a horse with EMS can be challenging, but working with a knowledgeable equine nutritionist can help create and monitor an appropriate diet. By focusing on reducing NSCs and providing balanced nutrition, horse owners can effectively manage EMS and reduce the risk of laminitis.

For additional guidance or to get an individually formulated diet tailored to your horse’s specific needs, contact Bluegrass Horse Feeds. Our team of experts can provide personalized advice and recommend the best feed solutions to support the health and well-being of your horse.