White line disease (also known as seedy toe) is a fungal infection of the horse's

hoof The hoof (plural: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits, yet the rum ...

. As the name suggests, it attacks the white line, which connects the sole to the hoof wall. It is sometimes mistaken for hoof wall separation disease, but is not to be confused because it is not genetic nor as severe.

Clinical signs

White line disease changes the typical light color of the white line to a black or dark gray color. It may also give off a foul odor. Lameness is often not present unless the disease is advanced. The disease may locate in the toe area of the hoof, giving rise to the name seedy toe. White line disease may not be noticed by the horse owner and is most often diagnosed by a

farrier A farrier is a specialist in equine hoof care, including the trimming and balancing of horses' hooves and the placing of shoes on their hooves, if necessary. A farrier combines some blacksmith's skills (fabricating, adapting, and adj ...

during routine hoof trims or shoeing. It may affect horses of any age, breed or sex, and can affect one foot or all four feet.

Causes

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 Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

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. 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.

Treatment

White line disease is sometimes treated by applying

borax Borax is a salt ( ionic compound), a hydrated borate of sodium, with chemical formula often written . It is a colorless crystalline solid, that dissolves in water to make a basic solution. It is commonly available in powder or granular for ...

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 Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), and by maggot therapy. In p ...

. Sometimes, if the problem is severe enough, the horse may need to be specially shod with a heart-bar shoe.

References

{{reflist Horse diseases Equine hoof