Animal Health & Welfare

In an SAC study of over 15,000 sheep, 25% of Scottish blackface and 56% of mules were found to have some degree of clinical footrot.

Footrot starts as scald (caused by Fusobacterium necrophorum), but progresses when a second species of bacterium, Dichelobacter nodosus invades the tissue. This organism takes advantage of the damage already done to the skin between the claws to invade the hoof itself. The disease is infectious and footrot spreads most readily in warm, moist weather outdoors and when sheep are housed - peaks of the disease in the UK usually fall between April and June, and then August to the end of October.

Diagnosis

• One or both claws may be affected
• There is separation of the horn from the underlying sensitive tissues of the foot - separation starts in the heel area and may spread across the sole and eventually up the wall of the hoof.
• There is usually a build up of characteristic smelly grey debris under the loosened hoof

Footrot Scoring

A scoring system has been devised to help eradicate footrot. The system plots the progress of the disease.

• Score 0 (normal) - No inflammation or sign of disease
• Score 1 (scald) - Area between digits is reddened then turns moist and cheesy
• Score 2 (early footrot) - Footrot organsim starts under-running the digit and breaking down hoof tissue
• Score 3 (severe footrot) - Footrot organism has penetrated the heel of the foot
• Score 4 (very severe footrot) - The disease progresses under the sole to reach the toe

Treatment

• As a flock problem footrot is best treated with a stand for up to 30 minutes in zinc sulphate solution.

For more detailed information on foot bathing, use the 'Foot Bathing' tab in the menu to the top left.

• For severe cases that do not respond to this, a long-lasting antibiotic injection should be used with culling of sheep that do not respond.
• Footrot should always be treated as an infectious disease and needs to be tackled on a flock basis, although it can be controlled on an individual basis via paring (click on the 'Paring' tab to the top left for more information).

Prevention

Regular assessment is the key to reducing the risks

• Regular inspection of feet - to restrict the spread, all sheep should go through a formalin or zinc sulphate footbath when penned for inspection.
• Separation of lame sheep into a hospital group with treatment of severe cases with antibiotic injection
• If possible, animals should be put back onto fields which have been clear of sheep for a week.
• Vaccination -  for more detailed information on vaccination, click on the 'Vaccination' tab on the top left.

Transmission of footrot is by carrier animals which act as a reservoir of infection. Those that do not respond to repeated antibiotic treatment must be culled from the flock.

A study beginning at SAC and involving a wide range of academic and industrial collaborators is investigating whether there is scope for selecting for footrot resistance in sheep.

To download the Defra booklet on Lameness in Sheep, use the link to the right