Johne's disease is a chronic wasting disease caused by the bacterium Mycobacterium avium subsp. paratuberculosis.
In Australia, Johne's disease has been found in cattle, sheep, goats, deer and camelids.
In some States Johne's disease is a notifiable disease.
The bacteria that cause Johne's disease live in the animal's intestines and cause thickening of the bowel wall that interferes with normal absorption of food.
The strain of the bacterium that mainly affects cattle, goats, deer and camelids is called bovine Johne's disease (BJD).
The strain of the bacterium that affects sheep is called ovine Johne's disease (OJD). Ovine Johne's disease can also affect goats.
Conditions when Johne's disease is likely to occur
The prevalence of Johne's disease varies in different regions of Australia. Information on prevalence zones and the BJD national strategic plan and OJD national management plan can be found on the Animal Health Australia website.
Both these plans are effective from 1 July 2012.
Bovine Johne's disease is most common in dairy cattle in south-eastern Australia but it can also occur in beef cattle. Western Australia is a bovine Johne's disease-free zone.
There are no ovine Johne's disease-free zones in Australia.
Identifying and diagnosing Johne's disease
Diagnosis of Johne's disease will require assistance from a veterinarian. Clinical signs that would lead a producer to suspect Johne's disease include:
- progressive weight loss
- emaciation in older animals despite a good appetite
Affected animals may also develop diarrhoea and bottle jaw.
Prevention and management strategies for Johne's disease
- Developing and implementing a farm biosecurity plan.
- Only purchasing animals with an animal health statement and only introducing low-risk stock onto the property.
- Implementing grazing management strategies to prevent the spread of the bacteria on-farm.
- Weaning early to limit infection of young calves, lambs and kids.
- Vaccinating sheep.
- On-farm management of ovine Johne's disease
- The role of grazing management in the control of ovine Johne's disease
- The role of vaccination in the control of ovine Johne's disease
More information on bovine and ovine Johne's disease is available on the following State department websites:
- Queensland Department of Agriculture and Fisheries
- New South Wales Department of Primary Industries - bovine Johne's disease, Ovine Johnes Disease
- Agriculture Victoria - bovine Johne's disease
- Biosecurity Tasmanian - bovine Johne's disease