Feeding performance horses with EMS means managing risk, not just calories: full analysis

A new The Horse commentary tackles a familiar but still tricky clinical question: how to feed a performance horse that has equine metabolic syndrome. The central takeaway is that these horses can often stay in work, but only if diet is built around controlling insulin response and minimizing laminitis risk, not simply around meeting performance-calorie targets. That framing reflects the current consensus view of EMS as a disorder of insulin dysregulation with potentially serious hoof consequences, rather than a problem limited to obviously obese or idle horses. (thehorse.com)

The background here matters. EMS has increasingly been defined by insulin dysregulation, abnormal adiposity, and a predisposition to hyperinsulinemia-associated laminitis. The Equine Endocrinology Group’s recommendations, revised in June 2022 and still prominently distributed by the group in 2024, emphasize that diagnosis and management should center on insulin status and laminitis risk. In parallel, The Horse has continued publishing practical explainers for clinicians and horse caretakers on which horses are predisposed, how diet affects insulin response, and why forage management remains the foundation of care. (equineendocrinologygroup.org)

For feeding, the broad direction is consistent across sources: reduce dietary nonstructural carbohydrate intake, avoid unnecessary concentrates, and make up nutrient gaps thoughtfully when calories are restricted. The Horse has reported that forage-only approaches often still require a ration balancer or vitamin-mineral supplementation, because limiting calories can also limit intake of sodium, chloride, copper, zinc, vitamin E, and selenium. Other expert commentary highlighted by the publication stresses that EMS horses need low-glycemic feeds to avoid exaggerated glucose and insulin spikes after meals. (thehorse.com)

That becomes more complicated in performance horses, which may need extra energy beyond what a strict low-NSC hay diet can provide. Industry nutrition commentary suggests the answer isn’t to abandon carbohydrate control, but to individualize the ration so energy needs are met without pushing insulin higher. Kentucky Equine Research, for example, notes that carbohydrate restriction is appropriate in EMS, but also warns that low-NSC diets are not one-size-fits-all and that nutrient sufficiency and workload still have to be considered. AAEP proceedings on the overweight performance horse make a similar point from the clinical side: excess condition increases the risk of insulin dysregulation and laminitis, so feeding for fitness in these horses requires more precision than simply adding calories for work. (ker.com)

On the exercise side, expert recommendations are also more nuanced than a simple “work them more.” AAEP proceedings summarizing consensus guidance say nonlaminitic horses should generally get low- to moderate-intensity exercise for at least 30 minutes, five or more times weekly, because exercise can improve insulin sensitivity. But horses with ongoing or previous laminitis need a much more careful plan, with low-intensity work on soft footing only after the lamellae are stable and with close monitoring for pain or soundness changes. That distinction is especially important for veterinarians advising pet parents and trainers who may equate competition status with metabolic safety. (pubs.aaep.org)

Expert and industry commentary broadly supports this individualized approach. The Horse quoted Katie Wilson, DVM, Dipl. ACVIM, advising that concentrates should be avoided unless absolutely necessary in EMS horses, and that reintroduction to grazing should be slow and paired with insulin monitoring. Merck Veterinary Manual likewise recommends using postprandial insulin measurements to assess whether a horse is metabolizing its current diet appropriately, with higher values signaling inadequate control and greater laminitis concern. (thehorse.com)

Why it matters: For veterinary professionals, this is less a story about a single feeding trick than about case management. Performance horses with EMS can look deceptively “well” because they’re active and in work, yet still carry significant endocrine and laminitis risk. The practical implication is that ration design, exercise prescriptions, and follow-up testing need to be integrated. Restricting starch and sugar without creating micronutrient deficits, deciding when concentrates are justified, and knowing when a horse is safe to increase workload all require veterinary oversight, especially in breeds and body types already predisposed to metabolic disease. (thehorse.com)

What to watch: The next step in this space is likely continued refinement of monitoring and treatment protocols, including how clinicians use dynamic insulin testing, post-feeding insulin checks, and, in difficult refractory cases, adjunct medical therapies. But for most horses, the near-term standard of care still appears to be disciplined diet control, appropriate exercise, and regular reassessment rather than any single new product or drug. (merckvetmanual.com)