NSMK 5 - Footrot in Sheep SDL

List the most important causes of lameness in sheep in the UK.

- Scald

- Footrot

- CODD (contagious ovine digital dermatitis)

All are transmissible and caused by bacteria

What is scald?

- Interdigital dermatitis

- Caused by a variety of bacteria that invade the surface layers of the skin between the claws (interdigital skin), following damage by moisture, frost, and/or mechanical damage from long grass, thistles etc.

- Common bacterium associated with scald is Fusobacterium necrophorum, which is ubiquitous in the environment and anaerobic

Explain the essential organism for footrot and its pathogenesis.

Dichelobactera nodosus

- Anaerobic bacterium

- In its first stage, footrot develops as scald

- Second stage of footrot is characterised by under-running of hoof horn and a characteristic smell

*Scald and early stages of footrot are clinically indistinguishable*

How can footrot spread within a population?

- D. nodosus are adapted to live and survive on the feet of sheep

- D. nodosus survives on pasture/bedding for up to 14 days, and in hoof horn clipping for a long time

- Infection can spread between sheep if they walk on the same surface

- Lame sheep can be treated with a combination of antibiotic injections and topical sprays

- Some sheep can get repeat infections, risking spread of infection to the rest of the flock

How is footrot treated?

- Long-acting antibiotic injection for the correct weight of the animal. Do not underdose

- Apply antibiotic spray

- Do not foot trim

- Separate infected sheep where possible

How can footrot be prevented?

- Do not select replacements from sheep with a history of lameness

- Cull sheep that have footrot more than twice

- Vaccination before high risk periods (e.g. housing)

- Treat even mildly lame sheep as soon as possible, including ewes in late pregnancy

- Avoid spread of infection by adopting biosecurity measures and prompt treatment

- Quarantine new sheep for at least 28 days and footbath on arrival

How is scald treated?

If there is not footrot on the far, treat with antibiotic spray,

If there is footrot on the farm, treat with antibiotic injection and spray. If incidence is high, foot bath the group and move to pasture that has been sheep-free for 14 days.