NZ Farmer - MPI to begin second round of milk testing for cattle disease Mycoplasma

Written by Gerard Hutching

Every dairy farm in New Zealand is about to have its milk tested again for signs of Mycoplasma bovis-infected cattle.

A Ministry for Primary Industries (MPI) spokesman said during the first round of testing in Canterbury, Otago and Southland, there was one detection of the disease. The programme was then extended into a national milk surveillance programme and a further two affected farms were found.

The purpose of the first round of national milk testing was to identify other possible regional clusters and build a complete picture of the disease.

The announcement of the second round of testing follows a prediction by a panel of experts appointed by the Ministry for Primary Industries that there would be a spike in the number of dairy herds testing positive in spring.

This was because dairy replacement stock, largely 2016 and 2017-born heifers, were the group most likely to be infected, but undetected.

The testing is part of a world first attempt to eradicate the disease, at a cost of $886 million, and involves culling about 150,000 animals.

M bovis is widespread throughout other dairy countries but was detected for the first time in New Zealand in July last year, although it is believed the disease was in the country at least in 2014.

MPI said milk samples from every New Zealand dairy farm would be taken shortly after the start of calving, when cows were most likely to be shedding the bacterium.

Samples will be collected from each farm approximately four weeks following the start of supply, with the first samples expected to be collected in the North Island late this month.

As 2016-born heifers calve for the first time and go into the milking herd, they will be tested for the disease.

MPI's director of response Geoff Gwyn said samples would be collected from each farm every two weeks up to a total of six samples over 12 weeks and tested by Milk TestNZ.

Farmers with "not-detected" results would hear on or before November 1 and those in the South Island November 15.

Meanwhile Federated Farmers said news that a lifestyle block in Rakaia with 24 animals had tested positive for the disease showed that all cattle farming operations had to take heed of the disease.

Dairy chairman Chris Lewis said another lifestyle block near Inglewood was under notice of direction while follow-up testing was done.

"Big, small, lifestyle or intensive/extensive, any farm operation with cattle is at risk and the owners and staff have a part to play in the biosecurity of the sector," Chris says.

"Outside Canterbury and Southland it is understandable that many small block holders were not aware of the implications of M bovis for them.

"But there is a wealth of information out there and everyone with cattle needs to do their homework."

Stock movements carry the highest risk for spreading of M bovis. Restrictions have been placed on all known risk properties so the risks of buying infected calves are low - but not zero.

On Wednesday the first North Canterbury dairy farm was confirmed as infected. While two other North Canterbury properties were earlier detected to have M. bovis, they were both beef properties.

Gwyn cautioned that the complex nature of  the disease meant results could not be taken as a guarantee the farm was free of the infection.