Hoof cracks are not all unusual in the horse world, and they come in a variety of depths, positions on the hoof, lengths, and causes. While hoof wall material is flexible, it, like most materials, possesses a given breaking point. In this case, vertical shear. The number of corrections that have been employed over the years is a rather lengthy list. A simplified version would include:
In some instances, combinations of the above are utilized.
Persistent toe cracks, like mentioned above, often have an underlying problem-that is, the crack is the result of underlying hoof wall damage. In many instances, the toe wall for varying reasons is separated on its underlying softer tissue attachments. This separation, if it exists, could be a result of mild rotation of the coffin bone (founder) within the hoof capsule, so-called "white line disease," the result of past hoof trauma (similar to having your own big toe stepped on with subsequent separation), and other problems affecting the hoof wall. In any case, there may be an underlying cause that needs to be addresed. Perhaps the best way to get further information is with radiographs (X rays) of the involved foot.
The initial attempt at repair utilized in this case was appropriate-it just simply didn't work on this horse. The basic principle of hoof wall crack repair is to stabilize the forces which keep the crack in place. Of all the methods listed above, my favorite employs the use of what is termed a composite repair.
The process begins by thoroughly exploring the involved area and removing any debris or foreign material that exists in and around the crack. Often, if sufficient instability is apparent, I will suture the crack (via drill holes in the walls) to help establish such stability. I will then fill and cover the defect and suture material with an acrylic compound. This, in turn, will be covered with a space-age fabric (Kevlar, Spectra, etc.) which is impregnated and covered with the same acrylic material. Following an appropriate curing of the material, the horse is appropriately shod. This technique, in my experience, has been the most likely to provide results.
It is important to reiterate that the success of repair is dependent upon two basic principles: 1) What is the cause and can we deal with it; and 2) establishing stability at the crack site. At this point in time, the gelding is not experiencing pain and lameness, but keep in mind that equation could change rapidly, therefore it is worth the attempt. Before proceeding further, I would have your veterinarian and farrier thoroughly examine this particular foot for underlying defects-the nature of the defect could alter the chosen method of repair.
William A. Moyer, DVM, is head of the large animal medicine and surgery facility at Texas A&M's College of Veterinary Medicine, and he is chairman of the American Association of Equine Practitioners' Equine Insurance Committee.