Ovine Johne's Disease Assurance

Ovine Johne’s Disease Assurance

Ovine Johne's Disease Assurance Program (SheepMAP)

The SheepMAP was developed in 1997 in response to calls from the Australian wool and sheep meat industries for a flock classification scheme to assure sheep breeders and their clients that participating flocks had been objectively assessed as having a low risk of having been infected with Ovine Johne’s Disease (OJD). It does not guarantee that a flock is absolutely free of OJD, but the higher the status a flock achieves, the greater the assurance that it is not infected. Therefore, participation in the programme will be most attractive to flock owners who wish to assure clients that their sheep have a low risk of having been infected. It is also attractive to producers wishing to sell breeding sheep as there is recognition for the additional assurance from the testing required and biosecurity in SheepMAP. It is important to note that the program does not apply to already infected flocks, which may be subject to regulatory control by the various states and territories.The SheepMAP is a voluntary scheme with the costs being borne by participating flock owners. 

At Rural Veterinary Services, all our Veterinarians are accredited by the Australian Johne's Disease Market Assurance Program to undertake Johne's disease testing.

Clinical signs of OJD

OJD is an insidious and progressive disease. It is not easily detectable and often no clinical signs are evident for the first few years.

Clinically affected sheep progressively lose weight (wasting) and usually die or are euthanised 3 to 8 months from clinical signs being observed.

The classic clinical sign of OJD is a distinct ‘poor’ tail end of the mob.

Due to a long incubation period, healthy looking animals can spread the disease bacteria for some time before becoming clinically affected. A slight increase in deaths and wasting from the disease may not be noticeable initially and may be mistaken for sheep already in poor condition due to old age or having internal parasite issues.

It is likely OJD will already be well established within a flock before deaths are noticed that are obviously attributable to the disease.

The level of disease in a flock is influenced by:

  • environment
  • management practices
  • higher rainfall
  • higher stocking rates.

Note, once the clinical phase occurs the condition is always fatal.