Laminitis is one of the most painful and potentially devastating conditions affecting horses. It involves inflammation and structural failure of the laminae — the interlocking tissue layers that suspend the coffin bone (distal phalanx, P3) within the hoof capsule. When the laminae fail, the coffin bone can rotate or sink (distal displacement) within the hoof, a condition commonly referred to as “founder.” Laminitis is a veterinary emergency, and early aggressive treatment is critical to the best possible outcome.

Overview

The laminae of the horse’s hoof function like Velcro, attaching the coffin bone to the inner wall of the hoof capsule. In laminitis, enzymatic degradation, ischemia (loss of blood flow), and inflammation destroy this attachment. The entire weight of the horse is then borne on failing tissue, causing extreme pain and structural collapse. Laminitis can affect one or more feet but most commonly involves both front feet simultaneously.

The three main categories of laminitis based on underlying cause are:

  • Endocrinopathic laminitis — The most common cause (approximately 90% of cases). Associated with Equine Metabolic Syndrome (EMS) or Pituitary Pars Intermedia Dysfunction (PPID, formerly Cushing’s disease). Insulin dysregulation is the central mechanism.
  • Sepsis-associated (inflammatory) laminitis — Triggered by systemic inflammatory conditions such as grain overload, retained placenta, colitis, or severe infection. Bacterial toxins and inflammatory mediators damage the laminae.
  • Supporting-limb laminitis — Develops in a weight-bearing limb when the opposite limb has a severe injury, causing prolonged overloading of the supporting foot.

Causes & Risk Factors

  • Equine Metabolic Syndrome (obesity, insulin resistance, regional adiposity — cresty neck)
  • PPID / Cushing’s disease (older horses)
  • Grain overload (accidental access to grain stores)
  • Retained placenta or severe post-foaling metritis
  • Severe colic, colitis, or pleuropneumonia
  • Prolonged weight bearing on one limb (contralateral limb injury)
  • Lush pasture access, especially in spring and fall (high nonstructural carbohydrate content)
  • Corticosteroid administration (can trigger laminitis in predisposed horses)
  • Breed predisposition — ponies, Morgans, and certain gaited breeds are at higher risk
  • Obesity

Symptoms

  • Reluctance to walk, shortened stride, or “walking on eggshells”
  • Characteristic “leaning back” stance to shift weight off the front feet
  • Increased digital pulses (bounding pulses felt at the fetlock)
  • Heat in the hoof wall
  • Sensitivity to hoof testers, particularly over the toe region
  • Lying down more than normal
  • Shifting weight from foot to foot
  • Resistance to having feet picked up
  • In chronic cases: widened white line, dropped or flat soles, divergent growth rings on the hoof wall

Laminitis is an emergency. If your horse is suddenly reluctant to walk, has bounding digital pulses, or is standing with a “rocked back” posture, contact your veterinarian immediately and begin cryotherapy (icing the feet) while waiting.

Diagnosis

  • Clinical examination — Characteristic stance, digital pulse assessment, hoof tester examination, Obel grading (Grade I-IV severity)
  • Radiographs — Lateral views of the feet to assess coffin bone rotation, distal displacement (sinking), sole depth, and degree of structural change. Serial radiographs track progression.
  • Venogram — Contrast study of hoof blood supply used in severe cases to guide prognosis and therapeutic shoeing
  • Endocrine testing — Baseline insulin, ACTH, and glucose levels to identify EMS or PPID as underlying causes
  • Bloodwork — To evaluate for systemic inflammatory conditions and organ function

Treatment & Medications

Acute Phase (Emergency)

  • Cryotherapy — Continuous icing of the feet in ice/water slurry to the level of the fetlock is the single most effective intervention in the developmental phase of laminitis. Studies show cryotherapy significantly reduces laminar damage when applied before or during the onset of laminitis.
  • Phenylbutazone (Bute) — The mainstay NSAID for laminitic pain. Typically dosed at 2.2-4.4 mg/kg orally twice daily, then tapered to the lowest effective dose to protect the GI tract and kidneys.
  • Flunixin meglumine (Banamine) — Alternative NSAID, particularly when systemic inflammation is present.
  • Acepromazine — A phenothiazine tranquilizer that causes peripheral vasodilation, theoretically improving blood flow to the feet. Used as an adjunct in acute cases.
  • Deep bedding and frog support — Soft footing (sand, deep shavings) and temporary frog support (Styrofoam pads, commercial support boots) to offload the hoof wall and distribute weight to the frog and sole.
  • Gabapentin — Used as an adjunctive analgesic for neuropathic pain associated with laminitis.
  • Opioids (butorphanol) — For breakthrough pain in hospitalized horses.
  • Stall rest — Strict confinement to prevent further laminar damage.

Chronic Phase (Rehabilitation)

  • Therapeutic trimming and shoeing — Working with a farrier experienced in laminitis cases to realign the hoof capsule, support the coffin bone, and encourage healthy hoof growth. Options include heart-bar shoes, egg-bar shoes, and impression material for sole support.
  • Treating the underlying cause — Management of EMS (diet, exercise, levothyroxine) or PPID (pergolide) is essential to prevent recurrence.
  • Dietary management — Restricting nonstructural carbohydrates (soaking hay, eliminating grain and lush pasture), use of grazing muzzles, and weight reduction in obese horses.
  • Pergolide (Prascend) — If PPID is diagnosed, this dopamine agonist is the treatment of choice.
  • Metformin or levothyroxine — Sometimes used as part of EMS management to improve insulin sensitivity.

Prognosis

  • Horses with mild laminitis (Obel Grade I-II) with minimal radiographic changes have a good prognosis with prompt treatment and management of the underlying cause
  • Moderate cases with coffin bone rotation but adequate sole depth may return to some level of soundness with aggressive farriery and medical management
  • Severe cases with significant rotation (greater than 15 degrees), distal displacement (sinking), or sole penetration carry a guarded to poor prognosis
  • Recurrence is common if the underlying endocrine condition is not controlled
  • Prevention through dietary management, weight control, and treatment of EMS/PPID is far more effective than treating established laminitis

Frequently Asked Questions

What is the difference between laminitis and founder? Laminitis refers to the inflammation of the laminae. Founder specifically describes the structural failure that occurs when the coffin bone displaces within the hoof capsule (rotation or sinking). All foundered horses have had laminitis, but not all laminitic horses will founder if treated promptly.

Can my horse recover fully from laminitis? Mild cases caught early can make a full recovery. Moderate to severe cases often result in some degree of permanent structural change in the hoof, and the horse may not return to previous performance levels. Long-term management and regular farriery are essential.

Is it safe to turn my laminitic horse out on pasture? During acute laminitis, strict stall rest is necessary. For horses with a history of laminitis or risk factors (EMS, PPID), pasture access should be carefully managed — avoid lush pasture, use a grazing muzzle, and limit turnout to times when pasture sugar content is lowest (early morning).

How quickly should I call the vet for suspected laminitis? Immediately. Laminitis is a time-sensitive emergency. Begin icing the feet while waiting for the veterinarian. The sooner treatment begins, the better the chance of preventing coffin bone displacement.

This information is for educational purposes only and does not replace professional veterinary advice. Laminitis is a veterinary emergency. Contact your equine veterinarian immediately if you suspect laminitis.