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Minimize Risk...Reduce Impact...Eliminate Johne's
- Uniform Program Standards for the Voluntary Johne's Disease Program (Effective September 2010)
- Approved Labs
- Case Studies
- Handbook for Vets & Beef Producers - 2011 Edition
- Handbook for Vets & Dairy Producers - 2011 Edition
- Johne's Approaches That Work
- Johne's Disease Integrated Program News
- Johne's Disease Newsletters
- Johne's in the News
- NAHMS Study
- Online Johne's Disease Veterinary Certificate Program
- Online Producer Education Course
- Risk Assessment & Management Plans for Johne's - 2011 Edition
- USAHA Johne's Committee Report
- Other Johne's Websites
Testing Accuracy Improved, More Cost Effective
The past decade has resulted in the development and commercialization of multiple accurate and cost-effective diagnostic tests for M. paratuberculosis.
The three common ways to test:
- Culture of fecal samples
- DNA probe on fecal samples
- Blood tests for antibodies to M. paratuberculosis.
Culture of the M. paratuberculosis from fecal samples — All animals can be tested for Johne's disease by doing a bacterial culture of a fecal (manure) sample. Yourveterinarian can help collect and submit samples for a Johne's fecal culture. Because of the extremely slow growth rate of M. .jpg)
paratuberculosis, this test usually takes eight weeks to 16 weeks and typically costs $15 to $25 per sample.
DNA probe on fecal samples — M. paratuberculosis bacteria can be detected in fecal samples by use of sophisticated DNA probe tests. While DNA probes are much faster than culturing the organism and can be done within three days, the commercial kits are not as sensitive as culture and are only able to detect infected animals when their infection has progressed to the stage where large numbers of M. paratuberculosis are being excreted in the feces. Therefore, animals in early stages of the infection are not detected. The other disadvantage of the DNA probe for Johne's disease is the cost of about $25 to $35 per sample. This cost may be lower in states that subsidize testing through their veterinary diagnostic laboratory.
Blood tests for antibodies to M. paratuberculosis — There are several blood tests for Johne's disease, with the ELISA considered most accurate and best standardized. Three ELISA-based tests are licensed by the USDA for detection of M. paratuberculosis-infected cattle. The ELISA is fast and simple, costs $8 to $10 per animal and can detect animals that are infected before they show signs of Johne's disease. Many veterinary diagnostic laboratories offer the ELISA for Johne's disease.
A three-part Hoard’s Dairyman article printed in 2001 describes test interpretation and can lead you from the simple to the complex: http://www.johnes.org/dairy/diagnosis.html
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Know Why You’re Testing
The “best test” will be determined by you and your veterinarian answering the question “What is the purpose of testing?”.
Testing purposes include:
- To classify herd as infected.
- To obtain a precise estimation of within herd prevalence.
- To control disease.
- For surveillance.
- To eradicate by wanting to eliminate M. paratuberculosis from the herd.
- To confirm a clinical diagnosis in a herd with no prior confirmed JD cases.
- To confirm a clinical diagnosis in a known M. paratuberculosis infected herd.
- To determine if a particular animal is Johne’s-free prior to purchase.
Additional information source: “Consensus recommendations on diagnostic testing for the detection of paratuberculosis in cattle in the United States” published by JAVMA, Vol 229, No. 12, December 15, 2006.
Where to Send Tests
The National Veterinary Services Laboratory (NVSL), Ames, Iowa, oversees a government program that identifies approved laboratories. Tests should be submitted for interpretation only to a qualified, approved laboratory.
A list of NVSL-approved laboratories is provided at Approved Labs.
