Managing virulent footrot in sheep and goats in Western Australia

Page last updated: Friday, 26 October 2018 - 9:20am

There are two forms of footrot in sheep and goats: virulent and benign. They are caused by infection with different strains of the bacterium, Dichelobacter nodosus.

Virulent footrot strains have the potential to cause more severe disease, whereas most benign strains cause a milder form that typically heals once the feet dry out.

Advanced virulent footrot is a painful, crippling condition. It is important to control or eradicate virulent footrot when it occurs in order to reduce production losses and to ensure animal welfare.

WA Footrot Control Program

The Department of Primary Industries and Regional Development, Western Australia (DPIRD) implements the WA Footrot Control Program at the request of industry, in order to limit the negative financial and welfare impacts of virulent footrot within WA. Industry funds the Footrot Control Program activities via the Sheep and Goats Industry Funding Scheme.

Border controls are also in place to reduce the likelihood of introducing virulent footrot from other jurisdictions in Australia.

Two forms of footrot

There are two forms of footrot, ‘virulent’ and ‘benign’, caused by different strains of D.  nodosus. The virulent strains of the bacteria have the potential to cause a more severe disease, whereas most benign strains cause a milder form that typically heals once the feet dry out. There are no quarantine restrictions for benign footrot, however producers must be vigilant and not present sheep with any footrot type lesions to saleyards. Read more about benign footrot.

Tests for footrot

To test for footrot, a veterinarian or stock inspector takes scrapings of skin from lesions between the toes of infected sheep to be cultured in the laboratory for bacteria. If D.  nodosus bacteria grows in the culture media, isolates are subjected to the gelatin gel test. The gelatin gel test categorises the protease enzymes produced by D.  nodosus on their stability when heated into two groups:

  • heat stable (S) strains, which cause virulent footrot or
  • heat unstable (U) strains that cause benign footrot.

Signs of virulent footrot

Both virulent and benign footrot start as inflammation of the skin between the toes seen as moisture, reddening and loss of hair. The additional signs of virulent footrot as it progresses are:

  • varying degrees of lameness
  • separation or under-running of horny material at the junction of the skin and the horn of the hoof, starting at the heel
  • usually more than one foot is affected
  • both toes of each affected foot are often involved and
  • loss of body condition and decreased wool production.

Diseases which can be confused with virulent footrot include benign footrot, foot abscess, and scabby mouth. More than one of these diseases may occur in an animal at the same time.

Lameness in several animals should always be checked by a veterinarian as the exotic disease foot-and-mouth disease can make sheep lame. Detecting an exotic disease early will limit the impact of the disease on the livestock industries and Australia’s economy.