Sheep Johnes Disease Welfare and Management

Johne's disease (paratuberculosis) causes progressive weight loss and diarrhea in sheep and cattle, with welfare harms accumulating slowly over years before terminal disease.

Key Facts

Johne's disease is caused by Mycobacterium avium subspecies paratuberculosis (MAP)
Infection typically occurs in the first year of life but clinical disease may not appear for 2-10 years
The disease causes progressive intestinal malabsorption leading to protein loss, weight loss, and diarrhea
There is no effective treatment - management focuses on culling and preventing new infections
MAP can survive in soil and water for up to a year, making environmental contamination a persistent problem
Vaccination reduces clinical disease incidence but does not eliminate infection
National accreditation programs help herds reduce prevalence through testing and culling

Welfare Considerations

Johne's disease causes a prolonged, insidious welfare decline. Affected animals show progressive weight loss and eventually profuse diarrhea while continuing to eat - their intestines simply cannot absorb nutrients. The condition causes increasing weakness over months as protein deficiency worsens. Sub-clinical disease creates periods of compromised immune function before obvious signs appear. The chronicity of the disease means welfare compromise persists for extended periods before diagnosis. Effective management through testing and culling of positive animals reduces the prevalence of this ongoing welfare problem, though elimination is very difficult once established in a flock or herd.

What You Can Do

Implement Johne's disease testing programs to identify clinically affected animals promptly
Cull test-positive animals to reduce the MAP burden in your herd or flock
Prevent calves and lambs from contact with manure of adult animals to reduce early-life infection
Consider vaccination programs to reduce clinical disease incidence in high-prevalence herds
Participate in national Johne's disease accreditation programs if available
Implement strict biosecurity to prevent introduction of MAP through livestock purchases