Equine Metabolic Syndrome (EMS) is a metabolic disorder characterized by insulin dysregulation, abnormal fat distribution, and a strong predisposition to [laminitis](/conditions/laminitis-founder). Affected horses typically develop regional adiposity — fat pads along the crest of the neck, over the tailhead, behind the shoulder, and in the sheath or mammary area — even when body condition elsewhere appears normal or only mildly increased. The core problem is insulin dysregulation (ID): the horse either produces excessive insulin in response to dietary carbohydrates (hyperinsulinemia) or the tissues fail to respond appropriately to insulin (insulin resistance), or both. Chronically elevated insulin levels directly damage the laminae of the [hoof](/anatomy/hoof-wall), making hyperinsulinemia-associated laminitis (HAL) the most dangerous and common consequence of EMS. EMS is most commonly seen in easy keepers — breeds such as Morgans, Arabians, ponies, Paso Finos, and warmbloods — although any horse can be affected. It typically develops in horses between 5 and 15 years of age. Unlike [Cushing s Disease (PPID)](/conditions/cushing-s-disease-ppid), which involves pituitary dysfunction, EMS is primarily a peripheral metabolic disorder. However, the two conditions can and frequently do occur together, especially in older horses. Diagnosis centers on documenting insulin dysregulation. The oral sugar test (OST) is the preferred dynamic test. General risk guidance: <50 uIU/mL = low risk, 50-100 uIU/mL = closer monitoring recommended, >100 uIU/mL = high risk of laminitis. Management centers on strict dietary control: limit non-structural carbohydrates (NSC) to below 10% of the total diet, eliminate grain and sweet feeds, soak hay to reduce sugar content, restrict pasture access, and provide regular exercise when sound. There is no cure for EMS — it is a lifelong management condition.
Cresty neck (hard, thickened fat deposits along the nuchal crest); Regional fat pads (tailhead, behind the shoulder, sheath/mammary area); Obesity or difficulty losing weight despite appropriate diet; Recurrent or unexplained laminitis episodes; Divergent hoof rings (wider at the heel than the toe); Lethargy or reduced performance; Increased digital pulses during active laminitis.
Equine Metabolic Syndrome (EMS) is a metabolic disorder characterized by insulin dysregulation, abnormal fat distribution, and a strong predisposition to [laminitis](/conditions/laminitis-founder). Affected horses typically develop regional adiposity — fat pads along the crest of the neck, over the tailhead, behind the shoulder, and in the sheath or mammary area — even when body condition elsewhere appears normal or only mildly increased. The core problem is insulin dysregulation (ID): the horse either produces excessive insulin in response to dietary carbohydrates (hyperinsulinemia) or the tissues fail to respond appropriately to insulin (insulin resistance), or both. Chronically elevated insulin levels directly damage the laminae of the [hoof](/anatomy/hoof-wall), making hyperinsulinemia-associated laminitis (HAL) the most dangerous and common consequence of EMS. EMS is most commonly seen in easy keepers — breeds such as Morgans, Arabians, ponies, Paso Finos, and warmbloods — although any horse can be affected. It typically develops in horses between 5 and 15 years of age. Unlike [Cushing s Disease (PPID)](/conditions/cushing-s-disease-ppid), which involves pituitary dysfunction, EMS is primarily a peripheral metabolic disorder. However, the two conditions can and frequently do occur together, especially in older horses. Diagnosis centers on documenting insulin dysregulation. The oral sugar test (OST) is the preferred dynamic test. General risk guidance: <50 uIU/mL = low risk, 50-100 uIU/mL = closer monitoring recommended, >100 uIU/mL = high risk of laminitis. Management centers on strict dietary control: limit non-structural carbohydrates (NSC) to below 10% of the total diet, eliminate grain and sweet feeds, soak hay to reduce sugar content, restrict pasture access, and provide regular exercise when sound. There is no cure for EMS — it is a lifelong management condition.
Cresty neck (hard, thickened fat deposits along the nuchal crest); Regional fat pads (tailhead, behind the shoulder, sheath/mammary area); Obesity or difficulty losing weight despite appropriate diet; Recurrent or unexplained laminitis episodes; Divergent hoof rings (wider at the heel than the toe); Lethargy or reduced performance; Increased digital pulses during active laminitis.