Johne’s Disease

Johne's Disease: Management Market Program

This is a voluntary program of testing and classification of herds according to level of Johne's disease infection. Herds that are not tested are automatically classified as "maximum risk." The program is available only for cattle and goat producers.

The program is voluntary, but there are advantages to testing: A healthy herd increases the bottom line.

Testing gives you a benchmark for managing the disease. And when you sell an animal as a replacement animal (not feeder or slaughter animals), you need to disclose in writing that it comes from an untested, therefore maximum-risk, herd. Otherwise, you risk liability if the animal either has Johne's Disease, or has been exposed to it.

Preventive Management Classification

"Preventive management level" classification means your herd has been officially tested and classified according to the test results. There are five possible classifications:

A - No animals test positive (test may be either on the whole herd, or on 30 head or 10 percent of herd)
B - Less than 5 percent of the whole herd tests positive
C - Less than 15 percent of the whole herd tests positive
D - More than 15 percent of the whole herd tests positive, or at least one animal out of 30 head or 10 percent of the herd tests positive
Maximum risk - Automatic classification for all herds not tested officially

Getting Started

You need to determine which animals are eligible, officially identify them, and decide what testing option is best. A licensed, accredited veterinarian must take the samples and send them to an approved laboratory. Either the ELISA blood test or a fecal (manure) culture. If the fecal culture results indicate contamination, the animals must be retested. Contamination will be considered a "no test." If the animal is vaccinated for Johne's Disease, you must use the fecal culture.

Eligible Animals

There are two categories of cattle eligible for testing: bulls 24 months and older, and all other cattle 36 months and older. You can test younger animals for diagnostic purposes, but the tests will not be included as part of the official herd classification.

Official Identification

Animals must be officially identified when tested. The official identification can be a USDA uniform series metal ear tag, breed association tattoo, association registration number, or registration freeze brand number that uniquely identifies the animal.

Options For Herd Testing

  • Random herd tests - The veterinarian randomly selects and tests either 30 eligible animals or 10 percent of the eligible animals, whichever is greater. He or she must collect all the samples on the same day.

  • Whole herd test - The veterinarian collects samples from all the eligible animals on the same day or consecutive days.

  • Split herd test -The veterinarian tests the entire herd of eligible animals, collecting the samples within a 12-month period or less. This requires you to have a test plan approved by the Department of Agriculture, Trade and Consumer Protection before you begin. Get a test plan form here.

If the herd contains 30 eligible animals or fewer, the whole herd test is the only option.


Test-positive animals must be permanently identified within 30 days of the test results with a "J" punched in the animal's left ear. With a written notice that the animal tested positive, you may sell the J-punched animal. If the animal is sold for slaughter, no written notice is needed.

Confirmation Tests

If your animals test positive with the ELISA blood sample, you can request a manure culture to confirm the results. The manure sample must be taken within 30 days of receiving the ELISA results. If you request a manure culture, the animal does not have to be J-punched until the manure test results are known, unless you sell it.

The manure test results takes 12 to 16 weeks. If the results are negative, the herd's classification will be adjusted, and animals testing negative will not have to be J-punched. If the manure test confirms the positive ELISA test, the animal must be J-punched within 30 days of the results. This applies to both official herd classification and diagnostic testing. If the manure tests are contaminated, the animal will need to be sampled again.

Annual Testing

Tests must be done every year within two months of the anniversary date - either two months before or two months after the anniversary date. If not tested within that time frame, the herd automatically reverts to the maximum risk category.

You are free to test animals outside of the official classification testing. Testing individual animals for diagnosis or for sale will not affect your official classification. In fact, testing for diagnosis is encouraged. However, animals that test positive must be identified with the J-punch.

Receiving and Using Classification

For the herd to be officially classified, the veterinarian has to check the appropriate boxes on the form he or she fills out when submitting the samples to the laboratory, and should be sure the laboratory will send results to the Department of Agriculture, Trade and Consumer Protection. Instructions to veterinarians for submitting samples are available here. When the department receives the results, we'll notify you of your classification by mail.

How you use the information is your choice. You do not have to make it public. But remember that if you sell replacement animals and want to avoid liability, you must provide in writing one of two things: either the herd's preventive management level classification or the maximum risk classification. Animals sold for feeding purposes or slaughter are exempt. Therefore, you do not need to provide a classification in writing. If you do want to make your good classification public, you can send written permission to the Wisconsin Department of Agriculture, Trade and Consumer Protection, your herd classification will be available to people who ask. Some farmers have found that this is a good way to find buyers or sellers.

When you buy replacement animals, you can and should ask the seller for the herd's official classification so you can make informed choices.