Barbaro and Equine Laminitis

Image Gallery The equine foot: 1) proximal phalynx 2) middle phalynx 3) distal, or third, phalynx 4) deep digital flexor tendon 5) coronary band 6) laminae, or layers, of the hoof wall. In laminitis, blood flow to the hoof is disrupted, causing laminae of the hoof to separate from underlying structures of the foot.

After suffering a broken hind leg in the May 20 Preakness Stakes, champion racehorse Barbaro developed a painful condition called laminitis in his other rear leg. Barbaro won the Kentucky Derby earlier this year, and was favored to win the Triple Crown before he misstepped in the Preakness.

Laminitis is a debilitating disease that occurs when the lamina, or sensitive tissue underneath a horse’s hoof wall, separates from the bone. Imagine having all of your fingernails and toenails peeled off simultaneously and you can appreciate the degree of pain felt by afflicted horses. Because it is so painful and debilitating, veterinarians choose to euthanize many horses with this disease.

The anatomy of the horse's foot yields clues as to why these animals are susceptible to laminitis. The horse is a single-toed animal, and the last bone, or phalynx, of the digit is encased in multiple layers of a tough protein called keratin, the same stuff our fingernails are made of. These protective layers comprise the hoof and are supplied with nutrients by a complex system of microscopic blood vessels.

Certain substances in the blood can cause changes in the blood flow to the hoof. The layers of the hoof begin to separate, causing severe pain to the underlying tissue. Worse, the most distant bone of the foot begins to rotate within the delaminating hoof as it is pulled by the deep digital flexor tendon. In severe cases the bone can rotate right through the sole of the hoof and come in contact with the ground.

While Barbaro underwent surgery to remove a portion of his afflicted hoof wall, his potential recovery hinges on the ability to keep weight off his rear legs while they heal. In the case of laminitis, the healing process is similar to regrowing a fingernail that’s been lost. Barbaro has reportedly been spending several hours a day in a sling designed to help him support his weight.

For more on laminitis and how it afflicted another Kentucky Derby winner, read Laminitis: A Horse's Worst Nightmare on MotherEarthNews.com.