White line disease, a disease of the hoof, appears to be a growing issue. It is a disease that causes the deterioration of the inner hoof wall. If undetected, white line disease can progress until it causes complete separation of the hoof wall and laminae, resulting in the rotation of the coffin bone.
White line disease is not an issue of stable or hoof cleanliness. Horses become more susceptible to white line disease if their hooves are cracked, have suffered a major trauma, are unbalanced or have chronic infections like abscesses. It affects all breeds of horses and can be found in one or all hooves.
The disease is caused by a bacteria/fungi combination. These bacteria and fungi are opportunistic in that they normally are found around the pasture or barn but become pathogenic when given the opportunity to creep into a cracked hoof and thrive in the anaerobic (non-oxygen) environment. They symbiotically coexist in white line disease.
The initial stages of infection do not cause lameness, and, in fact, by the time the horse is lame, the disease has done a tremendous amount of damage.
Early signs include a hollow sound when the hoof is tapped with a hammer, a dished or bulge shape in the hoof, tender soles, heat and a white line that is soft and chalky. If the horse has lost a shoe and a chunk of hoof with it, that might signal white line disease.
A veterinarian and farrier should work together to determine the best course of treatment. X-rays may be necessary to determine the extent of the damage to the inner hoof wall as well as to the coffin bone. If the farrier needs to perform therapeutic shoeing, he will also need access to those x-rays.
The treatment for white line involves a resection of the outer wall to expose the diseased inner hoof wall and remove damaged tissue. Therapeutic shoeing (like a heart bar shoe) supports the weakened hoof wall if necessary. The affected area must remain open and exposed to air and light. Medication may be applied to the affected area including merthiolate, betadine or 2% iodine.
The amount of exercise that the horse may perform after resection depends on the extent of the damage and resection.
The horse owner is to keep the area clean and dry, ensuring that the resected area is cleaned free of manure and mud. If the resection occurs in the summer, and the horse owner bathes her horse, she should ensure that she towel dries the hoof and the resected area so that it does not sit wet for long.
Once a resection has been done of the hoof wall, the horse is susceptible to developing abscesses until the resection has grown out. Horse owners that have horses with white line resection should keep on hand drawing hoof poultices and packing. One sign of an abscess is the “broken leg lameness,” where the horse is extremely lame on the leg that has had resection some time earlier.
Though abscesses typically require soaking in warm water with Epsom salt, the horse owner with a horse that has white line disease is at a conundrum. The white line resection area is supposed to remain dry; yet the most efficient way to encourage an abscess to pop is by soaking. In this scenario, a horse owner needs to confer with veterinarian and farrier to determine the best approach. They may determine that packing the hoof with drawing poultices or hot poultice pads may be in order.
After resection and follow up visits by the farrier to maintain the resection, the only thing the horse owner can do, besides keep the area clean and dry, is wait until the damaged hoof has grown out.
