White line disease

White line disease is most often seen in moist, humid areas with large annual rainfall totals. The exact organism that causes white line disease is not known, but it is known to be caused by bacteria in the soil getting into a weakened spot in the hoof wall, such as a quarter crack, which then sets up a fungal infection that leads to the disease.^{[citation needed]} Hoof infections are often attributed to poor management, but with white line disease this is often not the case, as it is seen even in horses kept in very clean stables and facilities.

White line disease is sometimes treated by applying borax or bleach solution to the affected area of the hoof, but this is not often successful. A recommended method of treatment is to cut away the hoof wall over the affected area, known as hoof wall resection or debridement. Sometimes, if the problem is severe enough, the horse may need to be specially shod with a heart-bar shoe.^{[citation needed]}