Johne's Testing Question

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Oct 20, 2008
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My local diagnostic lab (at my university) doesn't do Johne's testing and recommended me to Cornell. I was looking on the Cornell website and it says they don't recommend Johne's testing on bovines under 18 months. I was just curious as to why this is.
Serum antibodies are detected by ELISA's and this is a strong indication of M.paratuberculosis infection. The stronger the result the more antibodies to MAP are in the serum sample and the more likely the animal is to be infected.

Under 18 months the animal most likely will not have a strong amount of serum antibodies thus will not be detected by ELISA's leading you to a false result.

I found the web site a while ago and it has a quiz that is very informative for cattle as well a goats..Unfortunately I got almost 100% because of my own experience with Johnes..

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