Laminitis in Horses

Laminitis is an inflammation of the laminae, the connection of tissue between the hoof wall and the surface of the coffin bone (pedal bone). It leads to extreme pain, instability and in severe cases, a seperation between the hoof wall and bone, leadin the coffin bone to rotate.
Laminitis is commonly divided into three phases: developmental, acute, and chronic.

Developmental: The developmental phase is the beginning of the injury to the laminae. Horses typically do not show clinical signs, but the primary disease and pathological processes are underway.

Acute: During this phase, which can last hours to days, the first signs of lameness are observed. Rotation and displacement of the coffin bone may occur, but not all horses develop bone displacement. Horses may exhibit increased digital pulses, increased hoof temperatures, swelling in the limbs, constant weight shifting, subtle or obvious lameness, a stance indicating discomfort, unwillingness to move, and reluctance to rise.

Chronic: Clinical signs that last more than a week are diagnosed with chronic laminitis. During this phase, pain and lameness are caused by displacement of the coffin bone, the extent of which may be observed on radiographs. Affected horses exhibit increased digital pulses, varying degrees of lameness, and weight loss. Hooves may have a cleft at the coronary band and a characteristic “dished” appearance. Growth rings on the hooves may be noticeable in longstanding cases. Some horses develop white line separation, seedy toe and abscesses. In severe cases, the coffin bone can penetrate through the sole of the hoof.