Johne's Disease in Sheep: Chronic Wasting and Welfare Management

Johne's disease (paratuberculosis) is a chronic intestinal disease of sheep caused by Mycobacterium avium paratuberculosis, causing progressive wasting and eventually death in affected animals.

Key Facts

Johne's disease affects sheep, goats, cattle, deer, and other ruminants worldwide
Animals are infected in early life but may not show symptoms for years (iceberg effect)
Clinical signs include progressive weight loss, poor wool production, and soft feces
There is no effective treatment - disease is invariably fatal once clinical signs appear
Flock prevalence can be 20-30% in affected herds with subclinical infection
Diagnosis is difficult - blood ELISA tests have low sensitivity in early infection
Control programs combining testing, culling, and management changes can reduce prevalence

Welfare Considerations

Johne's disease causes prolonged, progressive suffering. Affected sheep gradually waste away over months to years, unable to maintain body condition despite appearing to eat normally. The malabsorption caused by intestinal damage means these animals are chronically nutrient-deficient. As disease progresses, affected sheep become increasingly weak, have difficulty keeping up with the flock, and are more vulnerable to other diseases and predators. The welfare obligation is clear: regular monitoring to identify and humanely cull affected animals before they reach the terminal stages of disease is essential to minimizing suffering in affected flocks.

What You Can Do

Implement a Johne's disease monitoring program with your flock veterinarian
Use risk assessment tools to identify management practices increasing transmission
Test animals showing chronic weight loss unresponsive to other treatment
Cull confirmed positive animals promptly and humanely - do not allow terminal decline
Prevent spread through colostrum management: only use colostrum from negative ewes
Join a Johne's accreditation scheme if available to reduce disease risk over time