Technical information for veterinarians

Laminitis and Founder

What is laminitis and founder?

Equine laminitis is a vascular disease associated with areas of ischemia or hemostasis within the laminae. The laminae secure the coffin bone/distal phalanx to the hoof wall. Inflammation associated with delamination interferes with the wall/bone bond. In advanced laminitis, the coffin bone becomes detached from the horny wall and may rotate or sink. In lay terms, this is known as “founder,” from the maritime term meaning to sink.

Symptoms/diagnosis of laminitis and founder

Three phases of laminitis in horses are identifiable: developmental, acute and chronic.

Developmental laminitis

This phase defines the period between the initiation of factors that result in delamination, and the emergence of clinical lameness. While owners are unable to identify possible laminitis at this stage, a vigilant veterinarian who knows what breeds and conditions present risk factors, will initiate appropriate therapies. (See Horses at Risk for Laminitis.)

Since pre-existing illness leads to laminitis, the symptoms of early laminitis are also the symptoms of the precipitating illness. Digital pulses and distal limb temperatures may be increased or decreased but no lameness is evident.

Occasionally, no development phase can be recognized; the horse is simply found to be in the acute phase with no apparent ill health preceding or accompanying it.

Acute laminitis

This may be defined as the period between the clinical onset of lameness and the stabilization of laminar degeneration/breakdown. It may be as short as 8 – 12 hours’ duration if the horse is exposed to black walnut shavings, or 30 – 40 hours in the case of carbohydrate overload. (See Etiology of Laminitis.)

Symptoms of the primary illness will be present along with lameness — usually in the front feet. On occasion, all four feet will be affected. When the forelimbs are affected, the horse will shift weight to the back legs, with the front legs extended. This is the typical “founder stance.” In response to the pain associated with the condition, the horse may refuse to stand or walk. In the early stages, identifying the condition may require turning the horse in a circle, preferably on a hard surface. An affected horse’s gait is typically short with rapid foot placement, hence the term “walking on eggshells.”

At this stage, the digital pulse will be increased and the hoof will have an elevated temperature. There will be pain when the toe is compressed with hoof testers and there may be a depression of the skin proximal to the wall of the hoof, suggesting rotation or sinking of the distal phalanx.

At this stage, it is wise to X-ray the hoof, for baseline purposes, and to determine the position of the distal phalanx relative to the hoof capsule.

Acute laminitis occurs anywhere from 24 – 72 hours after the initial damage to the basement membrane and causes considerable pain. An affected horse may refuse to stand, and have increased breathing and pulse rates in response to pain.

Chronic laminitis

This occurs when displacement of the distal phalanx has taken place but no active laminar necrosis is present. Horses with this condition are likely to get recurrent episodes of acute laminitis.

Abnormal growth of the hoof may be present. When the dorsal laminae are affected, diverging rings may be noted around the hoof wall. These will be wider at the heel than the toe, indicating that growth at the toe is slower than the heel.

The degree of lameness present depends on the use of the horse and quality of care.

Radiological changes at this stage will include improper alignment of the distal phalanx and hoof wall combined with the remodeling and osteolysis of the distal phalanx.

Etiology/pathology of laminitis and founder

Many seemingly unrelated causes can give rise to laminitis. To date, no one has pinpointed the precise mechanism by which specific health factors generate the conditions that cause separation and degeneration of the laminae.

Causal factors of laminitis include the following:

  • Excess of carbohydrates. (Too much grain, lush pasture.)
  • Excessive weight, particularly unilateral weight. Draft horses are particularly prone to laminitis.
  • GI problems and stress/shock, including:
    • enteritis, intestinal occlusion
    • colitis, peritonitis
    • metritis, retained placenta
    • pneumonia/pleuritis
  • Management factors:
    • prolonged transportation
    • excessive work on hard surfaces
    • bedding containing black walnut shavings
    • ingestion of cold water when the horse is overheated
  • Endocrine abnormalities:
    • Cushing’s syndrome (hyperadrenocorticism)
    • insulin resistance (equine metabolic syndrome)
    • hypothyroidism
    • administration of glucocorticoid drugs
  • Renal problems
  • Immune disorders
  • Respiratory problems

Treatment for laminitis and founder

The earlier treatment for laminitis is initiated, the better. If laminitis is suspected, or the horse has been exposed to a risk factor (e.g. carbohydrate overload, shock, black walnut shavings), treatment should begin immediately.

Treatments for laminitis vary according to the severity of the condition but include:

  • Encouraging the horse to lie down to relieve pressure on the hoof/hooves.
  • Imposing dietary restrictions to prevent overeating and obesity.
  • Treating with mineral oil via a nasogastric tube to purge the horse’s digestive tract. This will limit the absorption of bacterial toxins, especially if the horse has overeaten.
  • Administering fluids if the horse is ill or dehydrated.
  • Administering drugs and/or natural medicines, such as antibiotics to fight infection, anti-endotoxins to reduce bacterial toxicity, anticoagulants and vasodilators to improve blood flow to the feet. (Corticosteroids are contraindicated for laminitis as they can cause it to worsen.)
  • Administration of painkillers. Since moderate to intense pain often accompanies laminitis and founder, the veterinarian will likely prescribe painkillers and/or anti-inflammatories for the horse. These may include NSAIDs.
  • Use of a magnetic hoof pad. This recently introduced treatment is believed to increase local circulation and help relieve pain.
  • Stabling the horse on soft ground, such as sand or shavings.
  • Opening and draining of any abscesses that may develop.
  • Co-operation with the horse’s farrier. (Corrective shoeing is often very effective, particularly in preventing founder.)
  • Early treatment of the primary problem. (A delay of even a few hours can literally be the difference between continued healthy living and euthanasia.)

Horses at risk for laminitis and founder

The following risk factors exist for laminitis and founder:

  • Horses on a high grain diet
  • Ponies
  • Heavy breeds, such as draft breeds (large body weight)
  • Overweight horses
  • Unrestricted grain intake (if the horse breaks into the feed area, for example)
  • Horses on lush pasture

Preventing laminitis and founder

Laminitis is a disease that is avoidable when proper horse management is practised consistently.

Horse owners wishing to prevent the condition should observe the following:

  • Avoid feeding excesses and keep the horse at a reasonable weight.
  • Watch for and avoid grass blooms on pastures. Pull the horse off the fields and onto a dry lot if necessary. Feed hay in the morning and turn the horse out after dew has evaporated from the grass.
  • Keep grain in closed bins and the door to the feed room closed.
  • Give the horse unlimited access to fresh, clean water, except immediately after exercise, when the amount should be regulated.
  • Make changes to routines slowly and progressively, to avoid stress.

Natural options for Laminitis and Founder


Recovery®EQ with Nutricol®, is an elite proprietary performance and wellness supplement for horses that enhances quality of life.Recovery®EQ improves healing by increasing circulation of nutrients to affected cells and extracellular structures, halting tissue damage and decreasing inflammation. It may be used on its own or in combination with prescribed medications. Ask your veterinarian how Recovery®EQ can help your horse.

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Recovery®EQrated as “Best Performer Overall” as a pain-relieving supplement for joint pain, back pain and tendonitis – comparison of natural joint care supplements.

Review in the prestigious Horse Journal inJune 2006:

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For more information on helping your horse stay healthy, please see Tips for a Healthier Horse