Laminitis is inflammation of the laminae, the tiny, interlocking fingers that attach the coffin bone to the hoof wall. A complex sequence of events occurs during laminitis, potentially altering blood flow or circulation in the foot, resulting in damage to this tissue. When the damage is severe enough, the laminae die and the coffin bone is no longer supported in the hoof. If the bone rotates or sinks in the hoof, the horse is said to have “foundered”.The leading cause of laminitis is pasture (grass sugar) overload, but it can occur after any number of compromising conditions in the body, including:
Your veterinarian will perform a complete physical examination to determine the extent of the laminitis and attempt to discover what may have caused it. He or she may take x-rays initially as a baseline, and again a few weeks later to look for differences in the position of the coffin bone.
Generally, most horses with laminitis benefit from non-steroidal anti-inflammatory drugs (NSAIDs) like bute (phenylbutazone) for pain and swelling. If the laminitis is due to a gastrointestinal disturbance such as colic or diarrhea, Banamine® (flunixin meglumine) may be given to fight endotoxins. Antibiotics will be administered if infection is present. Sometimes medications that dilate blood vessels, such as acepromazine or isoxsuprine, are given to help encourage better circulation in the foot. Horses that develop laminitis due to Cushing’s should receive daily Prascend® (the FDA-approved version of pergolide) to manage the underlying condition. Thyro-L® (levothyroxine) is being investigated as a treatment for the Insulin Resistance seen in Equine Metabolic Syndrome and may be a useful prescription drug in the battle against laminitis.
It is very important to provide mechanical support to the hoof during a bout of laminitis, and your veterinarian and farrier should work together to accomplish this. At first, stall rest may be recommended. Later, as the horse becomes more comfortable, short periods of hand walking may help increase circulation to the damaged hoof tissue.
Depending on the cause of the laminitis, your horse may be put on a restricted diet. If caused by pasture or grain overload, or if Cushing’s or Equine Metabolic Syndrome are suspected, then grass, grain, treats and other foods high in sugar may be off limits. A vitamin/mineral supplement may be necessary to meet minimum nutrient requirements for horses on restricted diets.