White Line Disease

© Ray Miller

Keeping abreast of all the necessary information in horse health care is a constant challenge, especially since new problems and solutions are always being placed before our eyes and ears. Horse owners want only the best for their animals, which is sometimes difficult considering they do not always have all the information needed to make an accurate diagnosis of a condition or determine the proper course of treatment that should be taken.

One such problem came to the forefront recently that has had owners, veterinarians and farriers alike stymied. The signs are hooves that chronically are fractured and poor - looking, with the hoof wall actually peeling away. The cause is commonly believed to be onychomycosis (sometimes known as white line disease), a fungus that exists in the dirt. Horses that previously had strong healthy hooves are showing signs of infection, as well as those who have had problems with hoof quality in the past.

This fungus has flourished in the wet and mild conditions that the Midwest experienced this past spring and summer, as have other regions of the country, particularly the northeast. Since the fungus is always present in the soil, all horses are exposed, but inexplicably, not all are susceptible. In a single horse, the animal may show signs in one, two, three or four hooves; in a herd any number of horses may exhibit the characteristic chips and cracks. Shod animals typically develop a worse case, as the nail holes provide an entrance, while the shoe caps the foot and provides an excellent environment in which the fungus can thrive.

Although unsightly, this fungus does not usually cause lameness. However, if the hoof wall chips so that the horse is walking on his sole the owner will probably notice tenderness. Problems will also arise if the cracking and chipping extend up to and involves the coronet band. Treatment is simple. Brush the dirt from the sides and bottom of the hoof and spray with an iodine solution; a dairy udder wash seems to be very effective. Be careful to avoid the frog area and the coronet band; iodine may dry them out. Continue the treatment periodically, depending on the severity of the infection. Remember that it takes a full year for the hoof to grow down, as it begins at the coronet band, so it will take time to evaluate the results of the treatment.

Research has just begun at the University of Minnesota by Dr. Tracy Turner, D.V.M. So far few facts have been absolutely proven, but it has been decided that the fungus cannot be induced into horses' that are not susceptible, and it is not transmitted from one location to another by horses, people or tools. Solid facts are rare at this point, but for more information review the tape "White Line Disease" done by East Texas Farrier Burney Chapman.