With the advent of winter Primary Industries and Regions (SA) are urging sheep producers to be vigilant in checking for virulent footrot.
As a result of ideal conditions over the past 12 months, PIRSA Animal Health staff have seen more cases of virulent footrot appearing in markets.
Producers are reminded that any sheep sent to market are detected with footrot they can receive a significant fine.
Quotes attributable to Chief Veterinary Officer, Roger Paskin
Footrot can be complicated and best regarded as an ecological phenomenon rather than a simple disease problem, expressing itself clinically when conditions are right.
Virulent and benign types can survive in perfectly healthy feet for extended periods of time with symptoms only appearing when conditions are right. Producers therefore need to remember that a clinically healthy flock isn’t necessarily footrot free.
A recent review of footrot data from the South East and the Mid North indicates a high peak in detections approximately six months after a high peak in rainfall.
We had a very wet spring in 2016 followed by a wetter than average summer and autumn. So should rainfall totals this winter and spring finish at above average or above average totals, we can then anticipate ideal conditions remaining until the end of the year.
Footrot requires three factors to be present before the disease becomes evident:
- The presence of the bacteria Dichelobacter nodosus. This is usually introduced through new stock being introduced onto the property. Occasionally, clean animals can become infected by walking or grazing on pastures where infected sheep have recently been.
- Having sheep susceptible to footrot infection. While no breed of sheep is immune to this disease, British breeds or crosses tend to have a greater level of immunity than Merino or Dorpers.
- Environmental conditions. Moisture and temperature are important factors in the transmission and expression of footrot with ideal conditions including:
- Average daily temperatures above 10C
- Rainfall greater than 50mm a month in spring and winter, over 125mm a month in summer and 60mm a month in autumn.
Footrot will not spread under hot dry conditions.
For more information on footrot visit http://www.pir.sa.gov.au/biosecurity/animal_health/sheep/health/footrot