Deer follow cattle with Johne’s early detection blood test

Deer breeders can quickly identify animals positive for Johne as a result of on-farm test work that road-tested cattle blood test on hinds.

Research published in Frontiers in veterinary science used the actiphage test on 132 deer at four farms to detect carriers of the disease by blood sampling.

The test successfully detected the Mycobacterium avium paratuberculosis subspecies in deer blood samples, scientists say.

This means farms can use the test to screen animals before moving them to reduce the spread of infection, said study author Dr Cath Reese of the University of Nottingham.

See also: Scientists develop faster, more accurate Johne test

Previously, the main test used in deer was an Elisa antibody test, which detects the presence of MAP-specific antibodies produced by the animal in response to infection.

However, commercially available tests are less effective at identifying animals in the early stages of infection before they begin to shed large amounts of bacteria.

How it works

  • Actiphage works by detecting MAP bacteria in blood or milk, rather than looking for antibodies
  • It releases genomic DNA from MAP cells
  • Only a few cells are needed for detection by polymerase chain reaction (PCR) assays
  • It can test for Johne’s disease and bovine tuberculosis from a single blood sample

The test invites slaughter

Arden Farms, near Market Rasen, Lincolnshire, examined their entire herd after finding Johne’s disease was lurking in older animals.

The farm has isolated infected animals and removed carriers to eradicate the disease.

It is the first farm to use the test for disease control on its 450 posterior unit, after the University of Nottingham invited it to participate in the study for PBD Biotech – the makers of the blood test.

Farmer Sarah Arden said Johne’s disease can stay in the herd for many years before the animals show symptoms, adding that it is a difficult disease to diagnose before testing for actiphages.

Ms Arden said: “There is an Elisa test that can be used to diagnose Johne’s disease in deer and that detects antibody responses. The sensitivity of these tests in the early stages of infection is not good, so they often only give a positive result after the deer shows clinical signs of the disease. ”

Use of screening

The farm is now using the test to select animals, to ensure that incoming animals are disease free.

Ms Arden added, “We picked the deer for their conformation and temperament, and now we can select them without Johne.

“The vet can easily integrate the blood test with other procedures to check the health of the animals.”

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