White line disease is a fungal infection of the horse's hoof. This infection results in a breakdown of the wall of the hoof which makes shoeing the horse and keeping shoes on difficult.
The part of the hoof known as white line is the inner layer of the wall. The white line is actually yellowish in colour and has a soft, fibrous structure. It can be seen on the underside of a healthy hoof as a thin line joining the walls of the hoof and the sole of the foot.
White line disease usually starts as a splitting of the hoof wall at the white line or as an infection around the nail holes. It first appears as a crack or cavity which appears between the white line and the surface of the hoof. As the infection progresses it eats its way upwards through the hoof which weakens the attachment of the inner and outer walls of the horse's hoof.
As white line disease progresses the crack or cavity in the hoof gets larger and a foul-smelling, crumbly substance, similar to cottage cheese, appears in this crack.
Advanced cases of white line disease have been known to progress through into the outer wall of the horse or pony's hoof, sole and sometimes even the frog.
A horse will not be lame during the stages of the disease, but lameness often occurs when the hoof wall is weakened so much it is impossible to keep the horse shod.
Several factors can contribute to the development of white line disease in horses - including the following:
If it is caught in the early stages white line disease will cause few problems - but if it is left untreated it can cause damage to the hoof wall.
The best way to treat the infection disease is to catch it early and treat it with a product that kills both bacteria and fungus.
Treatments which are useful for a mild case of white line disease include
Before using any treatment try to clean out and remove as much of the infection as you can from the wall of the hoof - scrub the hoof with clean water and clean any dirt out of the cracks - a cocktail stick or a wooden manicure stick can be used for this.
Be careful not to use too strong a disinfectant which will kill good organisms along with the bad bugs.
To try to prevent a horse or pony from getting white line disease it's important to thoroughly clean your horses hooves daily. If your horse is at grass on a muddy filled or is kept in his stable for long perionds it may be necessary to clean the feet twice a day.