Johne's Disease

Cattle Grazing

What is Johne's disease?

Johne's disease is caused by a bacterium (Mycobacterium paratuberculosis) that infects the intestinal tract of ruminants. Cattle are usually infected as calves but do not show clinical signs until three or more years of age. The disease develops slowly and eventually kills the infected animal. There is no effective treatment. Cattle with advanced Johne's disease have chronic diarrhea and continually lose weight despite having good appetites.

Johne's Reference Material and Links


Educational Links

Industry Links

Archived Text

The three components of the Johne's program are education, management and classification. All three aspects involve producer and veterinarian cooperation. Certification is available for successful completion of each component.

Educational Component

Producers and allied industry members complete the educational phase by attending a class taught by a Johne's disease certified veterinarian. Upcoming classes are announced in trade journals, extension newsletters and other sources. The California Dairy Quality Assurance Program and the California Cattlemen's Association keep lists of dairy and beef producers, respectively, who have completed this phase.

Management Component

Herd risk assessments are performed by Johne's certified veterinarians to evaluate current management and biosecurity practices. The evaluation is based on the risk of transmitting the Johne's organism. Emphasis is placed on:

  • Calf Management
  • Replacement Management
  • Biosecurity
  • Method of culling positive cows. A management plan is developed based on the assessment.

Herd Classification Component

The final component of the Johne's voluntary disease control program involves animal testing. Classification is broken down into test positive and test negative herds. For more information contact Designated Johnes Coordinators or local certified Johnes Veterinarian.

Any veterinarian who has completed a Johne's disease certification training is a Johne's certified veterinarian. They can offer education classes, assist in developing risk assessments, assist in developing herd plans, and help with the classification phase of this program.

More information about the Voluntary Johne's Disease Program, including program administration, elements, and procedures, contact Designated Johne's Coordinator: Randy Anderson, D.V.M. ,

Diagnostic testing is a tool to help producers make decisions and reach their goals for the prevention and control of Johne's disease in their herds. The Johne's certified veterinarian and producer determine which test will achieve targeted disease control. Two types of tests routinely used for Johne's disease:

  • Tests that measure antibodies in serum: e.g., ELISA
  • Tests that find the organism in manure: e.g., culture

A Johne's disease advisory committee was formed in 1999 to evaluate Johne's disease in California, and, if necessary, develop a disease control plan. Representatives from the beef and dairy industries, academia, private practitioners, the California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) participate in this on-going committee. This group developed the voluntary Johne's disease control program, which is part of the comprehensive National Johne's disease control effort.

Contact Us

CDFA Animal Health and Food Safety Services,
Animal Health Branch

1220 N Street
Sacramento, California 95814
Phone: 916-900-5002
Fax: 916-900-5333
Our offices are open 8:00 AM to 5:00 PM Pacific Time.