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Johne’s disease is a chronic gastrointestinal infection that mainly affects sheep and cattle.

First published:
12 December 2018
Last updated:

It is not notifiable in Great Britain.

Suspicion and confirmation

Contact your private vet if you suspect Johne’s disease.

Clinical signs

Signs of the disease are rarely seen before two to three years of age. There is usually a period of reduced milk output or reduced fertility before animals show signs of advanced disease. These include:

  • persistent and profuse diarrhoea
  • significant weight loss despite of good appetite
  • “bottle jaw” – a swelling under the jaw

Transmission, prevention and treatment

The disease is caused by Mycobacterium avium subspecies paratuberculosis. Diseased animals pass large numbers of these bacteria in their faeces. A single animal can pose a high risk to susceptible animals and calves in a herd. Diseased animals may also excrete the bacteria in milk and colostrum.

Cattle are most vulnerable in the first few months of life. Calves can be infected in the womb or more commonly by:

  • drinking contaminated colostrum
  • ingesting dung that may be present on unclean teats
  • contaminated feed
  • contaminated environment or water supplies

To help prevent the disease you should practice good biosecurity. If your herd is infected, you should follow a programme of testing and culling.