Name: Laminitis or "Founder"
Age: Any age, but more common in older horses (chronic laminitis)
Breed/Sex Predilection: Ponies are at a greater risk.
What is it? Inflammation of the laminae, which are the connections that suspend the coffin bone within the hoof. As the disease progresses, the coffin bone may begin to rotate or sink within the hoof and can even protrude through the sole. Laminitis can be acute or chronic and clinical or subclinical. Subclinical episodes are not evident to the owner, although laminitis is occurring on the cellular level. These episodes can be recognized in abnormal "laminitic lines" in the hoof several months after the episode.
Cause: Metabolic causes include Cushing's disease, Metabolic Syndrome, and consumption of large quantities of sugar in grass or feed. Mechanical causes include extended pounding of the foot on hard surfaces and chronic overweighting of the foot (possibly due to an injury on the other front or hind foot).
Diagnosis: Clinical signs include reluctance to move, and especially the "walking on eggshells" gait, where the horse keeps his front feet more in front of his body than usual while shifting more weight to the hind legs. Digital pulses in affected feet are usually stronger than normal, and horses are extremely reactive to hoof testers. Radiographs are an extremely important part of diagnosis and management of this disease and should be used to monitor progression and recovery as well.
Treatment: Stall rest, pain management, proper padding of feet during the acute phase, +/- corrective shoeing during the chronic phase. Eliminating the initial cause of the laminitic episode is very important.
Prognosis: Good to poor depending on severity of rotation and sinking, ability to control pain, and correction of the inciting cause.
Prevention: Metabolic: Weight loss through reduced volume of concentrates, low starch feeds, soaking hay, grazing muzzles, and exercise (when allowed to do so again). Mechanical: Decreased activity on hard surfaces. Properly padded feet when overweight-bearing cannot be avoided.