Yet another farm in New Zealand has tested positive for the contagious cattle disease Mycoplasma bovis.

The detection was recently identified by the Ministry for Primary Industries’ (MPI) testing programme.

It has been confirmed that the most recent property to test positive for the disease is a Van Leeuwen Dairy Group farm, which was already under a restricted notice under the Biosecurity Act.

This announcement comes as over 26,000 of the planned 39,000 tests have now been completed by the MPI’s Animal Health Laboratory.

It was not unexpected that further farms within the Van Leeuwen Dairy Group would test positive for the disease, according to Response Incident Controller Stephen Bell.

“The nature of this disease is that it spreads between animals that are in close, repeated and prolonged contact. The disease doesn’t always present symptoms and often doesn’t show up through just one test.

“This is why we developed a testing protocol which tests herds up to three times, at three to four-week intervals. Testing like this, over two to three months gives us the confidence we need that we have definite results for each farm. This latest detection is evidence of that protocol working.

It has meant there has been a long period of disruption and uncertainty for farms that are being tested but we have to be absolutely thorough in diagnosing positive and negative farms.

“It’s important for New Zealand that we take that time to get accurate results,” he said.

What is Mycoplasma bovis?

Mycoplasma bovis is a bacterium that causes illness in cattle; the disease has very little effects on other animals. It does not infect humans and presents no food safety risk, the MPI added.

Symptoms of the disease include: udder infection (mastitis); late-term abortion; pneumonia in calves; as well as arthritis in both calves and cows.

Not all animals show symptoms of the disease, but they can pass on the disease to other animals through close contact. This disease is not something that spreads across long distances via wind or water.

Testing programme

Meanwhile, the planned tests have focused on: the infected properties; stock movement traces from and to those properties; and the neighbouring properties.

Bell confirmed that no adjacent properties have, as yet, been identified as infected. The MPI has taken a multi-layer approach to testing in order to find out how widespread Mycoplasma bovis is, he added.

Before the thought of eradication becomes a possibility, the MPI has to be confident that the disease has not spread to farms outside the Van Leeuwen Dairy Group, Bell said.

“We cannot make long-term decisions that potentially have huge impacts on people’s lives without that knowledge. We need to be confident the disease is limited to the outbreak on the farms where we have detected it.

“As our picture grows and as more and more test results come back, the greater our confidence [will be] that the disease is being well contained on the known infected properties.

We know this is an enormously stressful time for the impacted farmers and also for the wider farming community.

“We are carrying out all our work with urgency to limit the impact on the farming community as much as possible,” Bell concluded.