Page 277 - The Veterinary Care of the Horse

separating the outer hoof wall from the laminae. Soil and droppings enter the cavity and

bacterial or fungal invasion cause the horn of the hoof wall to break down. The cavity
VetBooks.ir becomes filled with dry, crumbly, horn material. If left untreated, the lesion progresses
towards the coronary band and large areas of hoof wall may become separated from the

laminae. Painful abscesses sometimes form due to bacterial infection.

‘White line disease’ and ‘seedy toe’ are often used synonymously. However, ‘seedy toe’ is
a small, focal lesion confined to the front of the toe. White line disease is more extensive and
may occur at the toe, quarters or towards the heels.

Causes

Anything that weakens the white line can predispose a horse or pony to white line disease,

e.g:
• living in excessively wet conditions

• long spells of dry weather or being stabled can lead to excessive drying of the hoof and

cracks in the white line
• poor quality horn due to nutritional deficiencies

• chronic bacterial or fungal infection of the horn

• penetration of the white line by sharp flints
• previous white line abscesses

• the occurrence of abscesses under the sole adjacent to the white line.

Alternatively, anything that increases the mechanical strain on the white line by increasing
the forces between the dorsal hoof wall and the sole can contribute to the development of

seedy toe, e.g:
• long-toe, low-heel conformation

• inadequate hoof care so the toes become abnormally long

• widening of the white line in animals with chronic laminitis.

Clinical signs

These may include the following.
• Visible widening of the white line.

• Local discolouration of the white line due to bacterial infection or packing of the cavity

with soil.