Laminitis (founder)
Laminitis means inflammation of the laminae in the hoof of the horse. The laminae are sensitive tissues inside the hoof wall that keep the coffin bone attached to the inside of the hoof wall. Laminitis results from the disruption of blood flow to the sensitive and insensitive laminae within the foot. With this inflammation, the laminar attachments to the hoof wall weaken and break down. As the bonds weaken, the front tip of the coffin bone rotates downward toward the sole and causes intense pain. Even if the the bone does not rotate, the horse will be in pain. The exact mechanisms by which the feet are damaged are complex and not completely resolved. Although the signs of laminitis occur in the feet, the underlying cause is often a disturbance elsewhere in the horse’s body.
The horse tries to reduce the pain by walking with its feet out in front and moving in a manner to keep pressure off its toes. Laminitis most often affects the front feet but may affect all four feet. Laminitis can be caused by many factors such as overeating grain, eating lush grass, infections, stress, and trotting or running on hard surfaces (concussion).
Treatment includes medication and proper therapeutic hoof care. With a laminitis episode, there is a whole spectrum of things that can happen ranging from the horse getting better to the horse being chronically and severely lame. In the latter case, the horse may be lame for the rest of its life. If laminitis is suspected, consider it a medical emergency and notify your veterinarian immediately. The sooner treatment begins, the better the chance for recovery.
Signs of acute laminitis include the following:
Lameness, shifting when standing, “walking on eggshells”
Heat in the feet and increased digital pulse in the feet
Pain in the toe region when pressure is applied with hoof testers
A “sawhorse stance,” with the front feet stretched out in front to alleviate pressure on the toes and the hind feet “camped out.”
Signs of chronic (reoccurring) laminitis may include the following:
Dished hooves, rings in hoof wall that become wider as they are followed from toe to heel (note: these rings can come from other things too, and their presence does not mean the horse had to have laminitis).
Bruised soles or “stone bruises”
Widened white line, commonly called “seedy toe,” and/or abscesses
Dropped soles or flat feet
