ECEIM consensus statement on equine metabolic syndrome.

Equine metabolic syndrome (EMS) is a condition in which horses are predisposed to laminitis because their bodies regulate insulin abnormally, especially when overweight or on high-sugar diets. This consensus statement explains how to recognize EMS, how to test for insulin dysregulation, and how to manage it long term with diet, exercise, and occasional medications.

What this consensus statement is and why it matters

• Provides expert-agreed guidance from the European College of Equine Internal Medicine on defining, diagnosing, and managing equine metabolic syndrome (EMS).
• Emphasizes that insulin dysregulation (ID) is the key risk factor linking EMS to endocrinopathic laminitis, a painful and potentially devastating hoof disease.
• Aims to give veterinarians and owners a structured, practical approach to reduce laminitis risk and improve long-term outcomes.

Core concept: insulin dysregulation as the driver of laminitis risk

• Insulin dysregulation (ID) encompasses several related problems:
  • Abnormally high resting (basal) insulin concentrations.
  • Exaggerated insulin responses after eating sugars or starches (post‑prandial hyperinsulinemia).
  • Reduced tissue responsiveness to insulin (insulin resistance).
• High circulating insulin is strongly associated with, and can precipitate, endocrinopathic laminitis by disrupting normal hoof lamellar function and blood flow.
• Obesity and high non-structural carbohydrate (NSC) intake amplify ID, but EMS can occur in horses that are not obese if they are insulin dysregulated.

Who is at risk and common clinical clues

• Typical signalment includes “easy keeper” breeds and types (e.g., native ponies, Morgans, Paso Finos, draft crosses), often middle‑aged but possible at any age.
• History suggesting EMS:
  • Prior laminitis, especially linked to pasture access or dietary change.
  • Easy weight gain on modest rations; difficulty losing weight.
  • Seasonal worsening in spring/autumn when pasture sugars are high.
• Physical examination findings:
  • Generalized obesity (high body condition score) and/or regional adiposity (cresty neck, fat pads over tail head, shoulders, sheath/udder).
  • Signs of current or past laminitis (hoof rings, widened white line, sensitivity, altered stance).
  • Normal to high appetite; generally bright attitude unless laminitic pain is present.

Diagnostic approach: combining history/exam with laboratory testing

• Diagnosis is based on:
  • Compatible history and clinical signs (including obesity and regional adiposity).
  • Laboratory evidence of insulin dysregulation using resting or dynamic tests.
• Resting (basal) measurements under controlled feeding:
  • Serum/plasma insulin concentration measured after a standardized low-NSC hay meal or brief controlled fast.
  • May include glucose; elevated insulin with normal glucose is common in EMS.
  • Pros: simple, accessible. Cons: lower sensitivity; stress, pain, recent feed can confound results.
• Dynamic tests that probe the post‑prandial insulin response:
  • Oral sugar or oral glucose challenge tests to detect exaggerated insulin secretion after a measured sugar dose.
  • Pros: more sensitive for detecting subtle ID; reflects real‑world feeding. Cons: requires preparation, timing, and adherence to protocols.
• Tests of tissue insulin sensitivity (used selectively):
  • Field insulin tolerance tests or combined glucose–insulin tests to assess how tissues handle glucose/insulin.
  • Used when results are equivocal or for research/advanced workups.
• Additional supportive labs and considerations:
  • Leptin (often high in obese horses), triglycerides, and adiponectin (may be reduced) can add context but are not primary diagnostic criteria.
  • Screen for pituitary pars intermedia dysfunction (PPID) in at‑risk ages or phenotypes, as PPID can coexist and worsen ID.
  • Interpret results alongside clinical status; pain and stress (e.g., active laminitis) can elevate insulin.

Management priorities: long-term, multifaceted, and disciplined

• Primary goals:
  • Normalize insulin dynamics and reduce laminitis risk.
  • Achieve and maintain a healthy body condition and neck crest score.
  • Restore and preserve hoof health while building sustainable routines for horse and owner.
• Core pillars:
  • Dietary management focused on NSC restriction and controlled calories.
  • Exercise to enhance insulin sensitivity, when feet are comfortable.
  • Targeted pharmacologic aids in selected cases.
  • Consistent monitoring and veterinary guidance.

Dietary strategies: reduce NSC, control calories, meet nutrients

• Forage-first, low-NSC approach:
  • Base the diet on grass hay with appropriately low NSC; consider testing hay to guide selection.
  • Soaking hay can help reduce soluble sugars when needed; drain and feed promptly.
• Energy intake and weight loss:
  • Set a safe, gradual weight-loss plan (often targeting about 0.5–1% body weight per week under veterinary supervision).
  • Use weighed rations, slow-feed nets, and multiple small meals to control intake and reduce hunger behaviors.
• Avoid high-NSC feeds:
  • Eliminate or severely restrict grain mixes, sweet feeds, and molasses-containing products.
  • If extra calories are needed, use fat and fiber-based, low-NSC concentrates formulated for metabolic horses.
• Pasture management:
  • Limit or eliminate pasture access during high-sugar periods; use a grazing muzzle or dry lot as needed.
  • Recognize high-risk times (lush growth, cool sunny days, after frost) when pasture NSC spikes.
• Micronutrient balance:
  • Provide a low-NSC vitamin–mineral balancer to meet essential nutrients while restricting calories.
  • Ensure salt and fresh water access; consider omega-3 sources to support metabolic health.

Exercise: improve insulin sensitivity and support weight control

• Prerequisite: no active laminitic pain; if feet are sore, prioritize stabilization and stall rest per veterinary and farrier guidance.
• Program design:
  • Begin with low-impact, regular work (e.g., brisk walking progressing to trotting) on good footing.
  • Build toward frequent sessions (e.g., most days of the week) of moderate duration to enhance insulin action and energy expenditure.
  • Adjust intensity and surfaces to the horse’s fitness, hoof status, and any comorbidities.

Pharmacologic aids: adjuncts, not substitutes for diet and exercise

• When considered:
  • For horses with severe ID, marked obesity, or slow response to management.
  • As short-to-medium-term tools while lifestyle changes take effect.
• Common options discussed in practice:
  • Levothyroxine sodium to facilitate weight loss and improve insulin sensitivity in obese horses.
  • Metformin around meals to blunt post‑prandial insulin surges in some individuals.
• Important cautions:
  • Efficacy varies; medications work best alongside strict dietary control and appropriate exercise.
  • Use under veterinary supervision; monitor for response and adverse effects.
  • If PPID is present, treating it (e.g., with pergolide as directed by a veterinarian) can improve overall metabolic control.

Laminitis prevention and hoof care integration

• Risk reduction:
  • Stabilize diet and turnout routines; avoid sudden feed changes or pasture binges.
  • Maintain an appropriate body condition and cresty neck score.
  • Identify and manage seasonal risk periods proactively.
• Hoof management:
  • Regular farriery to support the hoof capsule and laminae; radiographs as needed to guide trimming/shoeing.
  • Prompt veterinary intervention at the first sign of foot soreness or stance changes.

Monitoring and follow-up: measuring progress and adapting the plan

• Track body metrics:
  • Body weight (scale or weight tape), body condition score, and cresty neck score at regular intervals.
  • Photographs and girth/neck measurements help visualize trends.
• Reassess metabolism:
  • Repeat insulin testing (resting or dynamic) after consistent management changes to document improvement.
  • Review diet, pasture access, and exercise adherence at each check-in.
• Team approach:
  • Close collaboration among owner, veterinarian, and farrier is essential for long-term success.
  • Set realistic milestones and adjust strategies based on response and season.

Key takeaways for veterinarians and owners

• Insulin dysregulation is the pivotal, modifiable risk factor for endocrinopathic laminitis in EMS.
• Diagnosis blends clinical recognition with appropriate insulin testing; dynamic tests often improve detection.
• Dietary NSC restriction and structured exercise are the foundation of therapy; medications are adjuncts.
• Success requires consistency, patience, and ongoing guidance—EMS management is a long-term commitment.