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Johne's Disease

Johne’s Disease (JD) is a serious wasting disease affecting a number of animal species. In Australia it has been found in cattle, sheep, goats, deer, and camelids. Cross-infection between species can occur, but different strains of the bacteria cause infection in different animals.

In all species, the disease is caused by the bacterium Mycobacterium paratuberculosis. It leads to thickening of the intestinal walls and an inability of the gut to absorb food. Animals are hungry and eat, but because they have reduced ability to absorb nutrients they lose weight, develop chronic diarrhoea and eventually die.

The JD bacteria can survive in the outside environment for several months, contributing to the spread of the disease.

Bovine Johne’s Disease

This strain of JD affects cattle, goats, camelids and deer.

While cattle can become infected at an early age through eating contaminated pasture or by drinking contaminated milk or water, the disease is slow to develop and BJD is rarely seen in young animals.

In Australia, the disease occurs more frequently in the southern states. Crookwell is in a Protected Zone for Bovine Johne’s Disease. This means it is considered to be a low prevalence disease, but cases have been recorded here.

Ovine Johne’s Disease

OJD results in significant losses on infected farms. Like BJD, it is an incurable, infectious wasting disease. The Crookwell district is classified as a Control Zone – this means this area has a very high prevalence of the disease in sheep and suitable management procedures should be undertaken.

In Crookwell, this involves biosecurity ie preventing the movement of stock, accidental or otherwise, and vaccination.

Australia has a long-term national management plan to prevent and control OJD and Crookwell Veterinary Hospital has veterinarians approved for participation in the OJD Market Assurance Program. Please speak with us about management and control of OJD on your property.

Johne’s Disease in Goats

JD causes similar wasting disease and mortality in goats. As in cattle, the disease is more often seen in dairy goats than meat or fibre goats, but all goat breeds may be infected if they come into contact with the bacterium. Both the BJD (more common) and OJD strains have been detected in goats.

National Johne’s Disease Control Program

While large areas of Australia are Johne’s disease-free, National Johne’s Disease Control Programs were instituted in 1998 for OJD, and in 2003 for BJD.

Part of the program involves the Australian Johne’s Disease Market Assurance Program, run by Animal Health Australia. This is an audited Assurance Program incorporating animal health risk assessment, testing, and movement controls, that provides a source of low risk animals for the various industry sectors.