Laminitis in Horses: The Complete Guide to Causes, Prevention, and Recovery

What Laminitis Really Is

Laminitis is inflammation and failure of the laminae inside the hoof. Those laminae are the Velcro-like structures that attach the coffin bone to the inner hoof wall, and when they start failing, the coffin bone has nothing holding it in place. Gravity and the pull of the deep digital flexor tendon do the rest, dragging the bone downward and sometimes rotating it through the sole. It is as bad as it sounds.

This is not a hoof problem in the way a bruised sole is a hoof problem. Laminitis is a systemic crisis that manifests in the feet. Something goes wrong elsewhere in the body (the gut, the endocrine system, the vascular system) and the laminae pay the price. The feet are the end of the line, the furthest point from the heart, dependent on delicate blood flow through tiny capillaries. When that blood supply gets disrupted, the laminae starve and die.

Every horse person should understand laminitis because it can happen to any horse. Not just the fat pony. Not just the Cushing's horse. Any horse, under the right (or wrong) circumstances. Grain overload, retained placenta, severe colic, even prolonged weight-bearing on one leg after an injury to the other. The triggers are diverse and sometimes unpredictable.

The Laminar Connection: Anatomy That Explains Everything

To understand why laminitis is so destructive, you need to understand what the laminae actually do. Picture the inside of a horse's hoof wall. It is not smooth. It is covered in approximately 600 primary epidermal laminae, thin ridges that interlock with corresponding dermal laminae on the surface of the coffin bone. Each primary lamina has roughly 100 to 200 secondary laminae branching off it, creating an enormous surface area of attachment.

The total surface area of the laminar connection in a single hoof is somewhere around 8 square feet. That is the size of a small tablecloth, all folded into the space between the hoof wall and the coffin bone. This massive interlocking surface is what suspends a 1,200-pound animal on four relatively small feet. The coffin bone does not sit on the sole like a foot in a boot. It hangs from the hoof wall via the laminae. The horse is essentially suspended inside its own hooves.

See the coffin bone, laminae, and hoof wall relationships in our 3D horse model →

When laminae fail, the coffin bone loses its suspension. In rotation cases, the pull of the deep digital flexor tendon on the back of the coffin bone tips the front of the bone downward. The tip of the coffin bone presses into the sole, sometimes penetrating it. In sinker cases, the entire bone drops within the hoof capsule, compressing the coronary band and the solar corium. Both scenarios are emergencies.

The sole corium and coronary corium are vascular tissues that produce sole horn and hoof wall, respectively. Crush these, and you lose the ability to grow new hoof. That is when cases become truly devastating, not because the initial inflammation cannot be controlled, but because the mechanical collapse destroys the structures needed for recovery.

Laminitis vs. Founder: Clearing Up the Confusion

People use these words interchangeably and that is understandable, but they describe different stages. Laminitis is the inflammation of the laminae. Founder is the mechanical failure that follows: displacement of the coffin bone, whether rotation, sinking, or both. A horse can have laminitis without foundering if the laminae are inflamed but still intact. Once the coffin bone moves, the horse has foundered.

The distinction matters because a laminitic horse caught early can sometimes recover completely with no permanent structural damage. A foundered horse has already sustained structural collapse that requires months or years of rehabilitation and may never fully resolve. Speed of intervention is everything.

What Triggers Laminitis

The causes fall into several categories, and understanding which one you are dealing with dictates treatment.

Endocrine Laminitis

This is the most common type by far and accounts for roughly 90 percent of laminitis cases seen in general practice. Two conditions drive it: Equine Metabolic Syndrome (EMS) and Pituitary Pars Intermedia Dysfunction (PPID, formerly called Cushing's disease).

EMS horses are insulin dysregulated. They over-produce insulin in response to sugars and starches, and that hyperinsulinemia directly damages the laminae. These are your "easy keepers," the ones who get fat on air and develop cresty necks and regional adiposity. Ponies, Morgans, Paso Finos, and certain draft breeds are genetically predisposed, but any breed can develop it.

PPID is an age-related pituitary gland dysfunction, most common in horses over 15. The pituitary produces excess ACTH, leading to elevated cortisol and secondary insulin dysregulation. The classic signs (long curly coat that does not shed, muscle wasting, pot belly, recurrent infections) often show up alongside or before laminitis episodes. Testing for PPID involves measuring resting ACTH levels, ideally in the fall when seasonal rise makes the test more sensitive.

Inflammatory / Sepsis-Related Laminitis

When a horse develops a severe systemic infection or inflammatory response, inflammatory mediators circulating in the blood damage the laminar vasculature. Classic scenarios include grain overload (a horse breaks into the feed room and gorges on sweet feed), colitis, retained placenta after foaling, or severe pneumonia. The gut is often the source: endotoxins from dying bacteria cross the compromised intestinal wall and wreak havoc.

Grain overload is particularly dangerous because it alters hindgut pH rapidly, killing fiber-digesting bacteria and allowing starch-fermenting bacteria to proliferate. The resulting lactic acidosis damages the intestinal lining, allows bacterial toxins into the bloodstream, and the laminae take a hit within hours. A horse that eats 20 pounds of grain in one sitting is a genuine emergency even before lameness appears.

Supporting Limb Laminitis

When a horse cannot bear weight on one leg (due to fracture, severe infection, or surgical recovery), the opposite leg takes all the load. Continuous, unrelieved weight bearing compresses the laminar vasculature in the supporting foot, starving the laminae of blood. This is what killed the great racehorse Barbaro. His right hind leg was shattered, and despite heroic surgical efforts, his left hind foot developed laminitis from bearing his weight around the clock.

Supporting limb laminitis is particularly cruel because it is predictable. Veterinary teams use cryotherapy, sling support, and frequent position changes to mitigate risk, but in some cases the duration of non-weight-bearing is simply too long for the supporting limb to survive intact.

Concussive Laminitis

Also called road founder, this results from excessive concussion on hard surfaces. A horse galloped on pavement, a horse with thin soles worked on rocky ground for hours. It is relatively uncommon compared to endocrine laminitis but still shows up, especially in horses with compromised hoof structure.

How to Spot It Before It Gets Worse

Early detection saves feet. Period. If you catch laminitis in the first 12 to 24 hours, before the coffin bone moves, the prognosis improves dramatically. Here is what to watch for:

The stance. A laminitic horse rocks its weight backward, trying to unload the front of the feet. The hind legs camp underneath the body, the front legs stretch forward. It looks like the horse is leaning away from something. In severe cases, all four feet are affected, and the horse stands rooted in place, trembling, refusing to move at all.

Bounding digital pulses. Place your fingers on the digital arteries at the back of the pastern and you will feel a strong, throbbing pulse. Normal digital pulses are subtle, barely detectable. A bounding pulse means increased blood flow or vascular disruption in the foot. It is one of the earliest and most reliable indicators. Learn to check digital pulses on a healthy day so you know what normal feels like for your horse.

Heat in the hooves. Run your hands down the hoof wall and over the coronary band. A laminitic hoof feels notably warm compared to normal. Temperature alone is not diagnostic (feet warm up after exercise, in the sun, on hot ground) but heat combined with a strong digital pulse and reluctance to move is a red flag that warrants an immediate call to your vet.

Reluctance to move. The horse does not want to walk. You pull on the lead rope and it plants its feet. Turning is especially painful because it requires the horse to load one foot fully while pivoting. A horse that suddenly refuses to walk out of its stall should have its feet checked immediately.

Lying down more than usual. Horses that are normally on their feet most of the day suddenly spending hours recumbent may be avoiding weight-bearing pain.

If you suspect laminitis, do not wait to see if it gets better tomorrow. Call your veterinarian now. While you wait, get the horse standing on soft footing (deep shavings, sand) and start icing the feet if you have the materials. Hours matter.

Acute vs. Chronic: Two Different Battles

Acute laminitis is the initial crisis: inflammation, pain, and the threat of coffin bone displacement. The goal is to prevent mechanical failure. This phase can last days to weeks, and the horse needs aggressive intervention during this window.

Chronic laminitis describes the aftermath: the coffin bone has displaced, the hoof capsule is distorted, and the horse needs months of rehabilitative trimming and management to grow a new, correctly connected hoof. Some chronically laminitic horses develop rings on the hoof wall (divergent growth rings, wider at the heel than the toe) that tell the story of past episodes.

The chronic phase is a grind. Hoof growth averages about a centimeter per month at the toe. To grow an entirely new hoof capsule takes 9 to 12 months, sometimes longer. During that time, the farrier trims every three to four weeks, gradually realigning the hoof capsule with the displaced coffin bone, encouraging new growth in the correct orientation, and removing distorted horn as it grows out. Progress is measured in millimeters.

Treatment Protocols That Actually Work

Pain management is priority one. A horse in severe pain will not eat, will not drink, and the stress response compounds the systemic problems. Phenylbutazone or flunixin meglumine (Banamine) at appropriate doses. For severe cases, a combination of NSAIDs plus gabapentin or other adjunct analgesics. Acepromazine at low doses is sometimes used because it promotes peripheral vasodilation, theoretically improving blood flow to the feet.

Mechanical support. Get weight off the laminae. Deep bedding (12+ inches of shavings or sand) allows the frog and sole to share load. Styrofoam pads taped to the bottom of the feet distribute pressure across the entire solar surface. Commercial laminitis boots like the Soft-Ride or Nanric Ultimate are designed specifically for this. In an emergency, duct-taping Styrofoam insulation board to the feet works surprisingly well as a temporary measure.

Restrict diet immediately. If the horse is on pasture, pull it off. If it is on grain, stop the grain. Feed low-sugar grass hay that has been tested or soaked for 30 to 60 minutes to leach soluble carbohydrates. Caloric restriction may feel cruel when the horse is already suffering, but feeding sugar to a laminitic horse is pouring gasoline on a fire.

Treat the underlying cause. If it is endocrine, blood testing for insulin and ACTH levels guides treatment. Metformin may be started for insulin dysregulation. Pergolide (Prascend) is the standard treatment for PPID. If the trigger was grain overload, your vet may administer mineral oil and activated charcoal via nasogastric tube to reduce further absorption. If it is sepsis-related, IV fluids and antibiotics address the systemic infection.

Radiographs are essential during the acute phase. They show coffin bone position, the degree of rotation or sinking, and the thickness of the sole. This information guides trimming and shoeing decisions and gives a baseline for tracking changes over time. Repeat X-rays at 48 to 72 hours can detect early displacement that was not present on initial films.

The Ice Therapy Revolution

Cryotherapy has emerged as one of the most effective interventions for preventing laminar damage during the acute phase. Research by Dr. Andrew van Eps at the University of Pennsylvania demonstrated that continuous ice immersion of the feet (distal limb cryotherapy) dramatically reduces the severity of laminar destruction in experimentally induced laminitis.

The protocol: submerge the horse's feet in ice water (maintained below 5 degrees Celsius) continuously for 48 to 72 hours starting as early as possible after the triggering event. This is not a 20-minute ice boot session. This is boots or buckets filled with ice and water, replenished every few hours, worn around the clock.

Practically, this means buying several bags of ice per day and monitoring the water temperature. Purpose-built cryotherapy boots make this easier. The horse stands in the boots in its stall, and you add ice as it melts. It is labor-intensive and messy. The barn aisle will be wet. Your back will ache from hauling ice. But the evidence supporting cryotherapy is strong enough that most progressive equine hospitals now consider it standard of care for at-risk horses.

When should you start icing? Ideally, before clinical signs even appear. If your horse broke into the grain bin two hours ago, start icing now, even though the feet feel normal. If a mare retained her placenta, ice the feet as a preventive measure. The laminar damage begins at a cellular level hours before the horse shows pain. By the time you see lameness, destruction is already underway. Cryotherapy buys time and reduces the severity of the hit.

For a detailed look at the vascular anatomy of the hoof and why cryotherapy works at a tissue level, explore our equine anatomy encyclopedia.

Dietary Management and Prevention

For endocrine laminitis (the most common type), long-term management centers on diet. Period. You cannot medicate your way out of a bad diet.

The rules are simple but non-negotiable:

• No pasture access during high-risk periods. Spring grass and fall regrowth are loaded with fructans and simple sugars. A grazing muzzle is better than nothing but does not eliminate risk for highly sensitive horses. A dry lot with hay is safer.
• Test your hay. Submit samples to Equi-Analytical or a similar lab. You want total non-structural carbohydrates (NSC = WSC + starch) below 10 percent. Many grass hays test between 8 and 15 percent. Timothy and orchard grass tend to be lower than ryegrass or fescue, but testing is the only way to know for sure.
• Soak hay if needed. Soaking hay in cold water for 60 minutes or warm water for 30 minutes reduces WSC by 20 to 40 percent. Drain and feed. Do not let it sit and ferment after soaking.
• Eliminate grain and sweet feed entirely. Replace with a ration balancer (low calorie, vitamin and mineral fortified, no significant starch or sugar). Brands like Triple Crown 30, Enrich Plus, or Vermont Blend provide nutrition without the caloric and glycemic load.
• Supplement magnesium and chromium. Both are implicated in insulin sensitivity. Magnesium oxide at 5 to 10 grams per day is commonly recommended. Evidence for chromium is weaker but many metabolic specialists include it.
• Manage weight aggressively. An obese horse with EMS that loses 10 percent of body weight often shows measurable improvement in insulin sensitivity. Use a weight tape monthly. Adjust hay quantity (minimum 1.5 percent of body weight per day in dry matter). Do not starve the horse. Slow, steady weight loss over months.

Exercise is the other critical piece for metabolic horses that are sound enough to work. Moderate exercise improves insulin sensitivity independent of weight loss. Even 20 to 30 minutes of walking under saddle or on a lunge line, four to five days per week, makes a measurable difference in insulin and glucose dynamics.

Learn more about the metabolic pathways and anatomical structures involved through our equine anatomy courses.

Long-term Recovery and What to Expect

Recovering from a laminitis episode is slow work. Set your expectations in months, not weeks. A horse that foundered with 8 degrees of rotation needs roughly a year to grow a new, realigned hoof capsule. During that year, the farrier visits every three to four weeks. Radiographs are taken periodically to monitor coffin bone position. The horse may wear therapeutic shoes or boots. Turnout is restricted to small paddocks with soft footing.

The good news: many horses recover to full or near-full soundness after a single laminitis episode, provided the underlying cause is identified and managed. First-time laminitis in a horse that has never had metabolic issues, triggered by a one-time event like grain overload, carries the best prognosis. The laminae heal, the hoof grows out normally, and the horse returns to work.

Recurrent laminitis is a different story. A metabolic horse that founders every spring because the owner will not keep it off grass will accumulate damage with each episode. The hoof capsule becomes progressively more distorted. Chronic coffin bone remodeling sets in. Sole depth decreases. Each episode starts from a worse baseline, and eventually the damage becomes unmanageable.

The takeaway: laminitis is often preventable, and prevention is infinitely better than treatment. Know your horse's metabolic status. Test insulin levels. Manage diet proactively. Catch the early signs. The horse that never founders is not lucky. Its owner is paying attention.