White Line Disease

There are many names for white line disease. It has been referred to as foot rot, hoof wall disease, hollow hoof, stall rot, and onychomycosis. Basically what happens is invaders (pathogens) break down the protein and collogen that make up the hoof wall. They usually enter the hoof through a compromised spot. Trauma, abscess formation, sole or toe bruising, nail holes, and fissures could be enables for these opportunistic invaders. Enzymes and endotoxins are produced by these invaders which cause the hoof wall at the stratum medium to deteriorate. The stratum medium is the area that connects the sensitive and insensitive laminae. It is believed that both bacteria and fungi work together for this destruction to occur.

In the beginning stages of white line disease, one may notice a gray, black or white line that looks chalky or flaky on the ground surface of the hoof. Breakage and/or cracking of the hoof wall may occur. When advanced, white line disease can undermine the hoof structure. When trimmed, often a cavity or deep cavern can be seen showing that much of the hoof wall has been destroyed. It looks like an empty shell. At this point it is often difficult to attach a shoe. The horse may become lame or even worse- there can be rotation of the coffin bone. If possible an egg bar or heart bar shoe might be used depending on where the underlying structures have been compromised.

It is important to stop white line disease in its early stages. It should be treated quickly and aggressively. The hoof must be balanced, have correct angles, be clean, and dry. The offending micro organisms flourish in a wet and dark environment. It is important to have the hoof exposed to the air. Medication such as merthiolate is often effective. There are many other preparations on the market that may be recommended by your vet or farrier. Removing the compromised hoof wall is often recommended. Depending on the severity of the white line disease the treatment time can be long. It takes approximately ten months to one year for the hoof to grow out. Biotin mixtures are frequently recommended, not as a cure, but to help the new hoof growth to be strong and healthy. This is a thumbnail sketch of white line disease. It is meant to help the horse owner identify white line disease and avoid major problems. If you suspect your horse may be starting with this problem, contact your vet and your farrier immediately.