October 2026 – Complete Your 2026 Johne’s Testing to Protect Your Herd

Have you completed your 2026 Johne’s disease (JD) herd test? If it is still outstanding, contact your vet or milk recording organisation to plan it. The results help you identify high-risk animals and make decisions to protect your herd and the next generation of calves.

The Irish Johne’s Control Programme (IJCP) uses two tests. The blood or milk ELISA test looks for antibodies produced by the animal’s immune system in response to infection. The ancillary PCR faecal test (ANC) looks for DNA from Mycobacterium avium subspecies paratuberculosis (MAP), the bacteria that causes JD.

Your vet can use these results to advise on managing or culling high-risk animals, identifying high-risk groups and making breeding decisions that reduce the risk to future calves. This makes testing a practical part of your herd health plan.

AHI is reminding IJCP members with outstanding herd tests to organise testing. Before booking yours, check the following:

• Check the interval between testing rounds – Allow at least six months (180 days) between the start of one Johne’s testing round and the next.
• Use milk recording where suitable – If your farm uses milk recording, it can save time and money when completing most of your Johne’s testing.
  • Organise this through your milk recording organisation (MRO).
  • Milk ELISA testing is best used during mid-lactation (May to October).
• Plan around TB testing – Johne’s testing can’t be carried out within 90 days of the first injection of a TB test.
  • If your herd undergoes frequent TB testing, speak to your vet before booking. Johne’s testing can give valid results after 60 days from a TB test, but discuss any test planned within the 90-day window with your vet.
• Choose the right time for milk sampling
  • Do not collect milk samples within seven days of calving.
  • Avoid sampling in the late stages of lactation.
  • Both can increase false-positive results, making it harder to identify high-risk animals.
• Include all eligible cattle – Test all cattle over two years old, including bulls. Bulls can have contact with the whole herd, so remember to include them in your testing plan.
• Check your animal list on ICBF – Use the Johne’s tools on the ICBF website to:
  • Generate a list of all eligible animals for testing on your chosen date.
  • Identify animals requiring additional faecal testing.

For eligible IJCP herds with positive blood or milk ELISA results and no previous disclosure of JD, ancillary PCR faecal testing (ANC) is fully funded. It helps your vet interpret ELISA results and assess infection in the herd.

A positive ANC result confirms that MAP, and therefore JD, is present on the farm. Once MAP infection is confirmed, animals with positive or inconclusive ELISA results are likely to be infected.

When an animal tests positive on ELISA:

• A positive ANC result confirms that the animal and herd are infected with MAP.
• A negative ANC result means no MAP DNA was found in the faecal sample. It does not rule out infection: an animal may have antibodies but not yet be shedding detectable MAP in its faeces. These animals remain classified as “suspect” and may pose an infection risk.

AHI is contacting IJCP members with outstanding 2026 ANC tests. If you receive a reminder, contact your vet to organise the test. Completing this follow-up is an important part of the programme and is fully funded in eligible herds that have not previously disclosed JD.

Still have testing outstanding? Contact your vet or milk recording organisation to plan your herd test, and your vet for any required ANC follow-up.