Johne’s Disease in Beef Cattle

Johne's disease is a slow, wasting disease that is hard to spot early. Calves usually pick it up young, and signs often appear years later, so prevention depends on management of the calving area and the herd.

Key points

Johne's disease is a slow wasting infection of the intestine.
Calves usually get infected young but show signs as adults.
Testing is imperfect, so use it as part of a plan with your vet.
Clean calving ground and clean udders reduce risk.
Be careful with purchased cattle and honest with buyers.

What Johne's disease is

Johne's disease is a chronic bacterial infection of the intestine. It reduces the animal's ability to absorb nutrients, leading to weight loss over time, even when the animal keeps eating. In beef cattle, diarrhea is less common than in dairy cattle, so thin cows with no clear cause can be the main sign.

The germ can survive in the environment for a long time, which makes clean ground and clean water important.

The disease is also called paratuberculosis. It is not the same as tuberculosis, but the two names sound alike, so ask your vet if you are unsure which one is being discussed.

How it spreads

Young calves are most vulnerable. They can become infected by swallowing manure from an infected adult, through contaminated udders, water, or feed, and sometimes before birth. Most infected animals do not show signs until adulthood.

Because of this long delay, many cases go unnoticed. An infected animal can shed bacteria before she looks sick, spreading the problem quietly.

Calves swallowing infected manure
Dirty udders at nursing
Shared water or feed contaminated by manure
Purchased cattle with unknown status
Calving areas used year after year without a rest

Signs to watch for

In the later stages, cattle lose weight and condition despite a good appetite, and may have poor hair coat. Some develop diarrhea, but many do not. These signs fit many other problems like parasites, poor teeth, or nutrition issues.

Do not decide on your own. Ask your vet to look at any thin cow and rule out other causes. Body condition scoring on the 1-to-9 scale helps you see change over time.

Look at cows in their third or fourth year and older, since signs usually appear in mature animals. Keep notes on cows whose condition drops without a clear reason.

Testing and what results mean

Testing for Johne's can be tricky, because an animal may be infected and still test negative early on. Your vet can explain which tests are available, what they can and cannot tell you, and whether herd-level testing makes sense for you.

Testing is most useful when it is part of a larger plan. Ask your vet to help you decide who to test, how to read the results, and what to do with them.

Herd risk assessments are another tool. Your vet can walk through your calving area, water, feed, and purchase history and point out where calves may be exposed.

Reducing risk on the ranch

Focus on the calf. Provide a clean calving area, remove calves from manure-contaminated ground, and make sure nursing calves are not exposed to dirty udders. Keep feed and water free of manure. Do not spread manure on pasture used for young calves.

Buy cattle from herds with good health programs, and ask your vet about testing and quarantine for purchases. Keep records of animals that have signs and the dam and offspring of any positive animal.

Small things add up. Keep feed bunks and water tanks high enough that manure cannot get in, and keep calves off ground where older cows have been standing.

Culling and herd decisions

Decisions about positive or suspect animals are tough. Your vet can talk through options, including culling, separating calves from affected dams, and watching offspring. The best choice depends on your herd, your goals, and the testing you have.

If you sell cattle, be honest with buyers about herd health. Follow any program or state rules that apply, and ask your accountant or lender about the financial effect of culling decisions.

Keep the offspring of any confirmed positive cow under watch, and talk with your vet about whether they should be kept as replacements.

Common mistakes

Ignoring thin cows, leaving calves on dirty ground, buying cattle without checking history, and relying on one test result are the usual errors. Another is hiding the problem from buyers. Be open with your vet and follow any rules about selling cattle. Follow label directions and withdrawal times on any product given to animals.

When to get help: Ask your veterinarian to evaluate any thin cow that has no clear cause, and to help you build a prevention plan for the calving area and for purchases. Follow label directions and withdrawal times on anything given to cattle.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

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