Horse Equine Metabolic Syndrome: Diet and Welfare

Equine Metabolic Syndrome (EMS) is a growing welfare concern in horses and ponies, driven by inappropriate feeding and causing painful laminitis episodes.

Key Facts

EMS is characterized by insulin dysregulation, regional adiposity, and predisposition to pasture-associated laminitis
Native and pony breeds — evolved for sparse forage — are most susceptible when given access to high-sugar grass or concentrate feeds
Laminitis secondary to EMS is one of the most painful conditions in horses; severe cases result in rotation or sinking of the pedal bone
EMS is estimated to affect 11–30% of horses and ponies in the UK, with obesity prevalence increasing over decades
Management requires strict dietary restriction, structured exercise, and often grazing muzzles — causing behavioral frustration

Welfare Considerations

EMS creates a welfare dilemma: management requires restricting natural foraging behavior, while unmanaged EMS leads to severe laminitis pain. Horses are trickle feeders evolved to graze 16–18 hours daily; dietary restriction for EMS management causes frustration, stereotypies (crib-biting, weaving), and gastric ulcers from extended fasting. However, uncontrolled access to sugary grass causes laminitis episodes that involve intense, chronic foot pain, reluctance to move, and behavioral changes indicating significant suffering. The challenge is balancing natural behavioral needs against metabolic disease management. Many horses live with poorly controlled EMS due to owner reluctance to impose strict management regimes.

What You Can Do

Maintain healthy body condition scores in horses and ponies; obesity is the primary preventable EMS risk factor
Use a grazing muzzle to allow turnout while restricting sugar intake — pair with environmental enrichment to reduce frustration
Test hay for non-structural carbohydrate content and soak it for 60 minutes to reduce soluble sugar levels
Seek a veterinary internal medicine specialist for insulin testing and EMS diagnosis if laminitis recurs
Connect with equine welfare organizations for evidence-based feeding and management guidance for native breeds