Important Mycoplasma bovis update: testing stepped up with new strain

// Biosecurity

Summer testing for Mycoplasma bovis (M. bovis) will be stepped up after the nationwide surveillance programme identified a new strain of the disease on one of the four confirmed positive properties, which are all in Mid Canterbury.

image of bull

Recently completed genomic testing from a single property, which was previously confirmed with M. bovis, has identified the strain.

This strain doesn’t behave any differently than the strain the M.bovis Programme has been dealing with, and existing testing will pick it up, as it has done in this case. It also doesn’t affect the efforts to eradicate M. bovis from New Zealand.

A thorough investigation is underway into historic pathways, which includes recorded and unrecorded animal movements dating back to 2018, imported feed and farm machinery, and frozen semen imported prior to the tightening of import health standards for bovine germplasm.

While considered a very low risk, frozen semen used on the affected property, which had been imported prior to the introduction of the new import health standard, is being looked at.

The M. bovis programme team is carrying out an investigation on the affected property. At this stage, there is no evidence to suggest that there has been any forward spread onto any farms that received cattle from this farm. 

The bulk tank milk and beef herd screening (alongside cattle tracing work) has not identified this strain anywhere else, but disease control is about being cautious, so the programme will be increasing the summer frequency of national bulk milk surveillance testing from once a month to every fortnight, as occurs over spring.

M. bovis is currently on just four farms compared to 40 at the height of the programme.

We are four years into a 10-year programme, and we remain on track for eradication. We are moving towards a national pest management plan for M. bovis much like that used for TB. The aim of that will be to monitor and deal with any disease that pops up over time.

If the investigation into pathways reveals that further action is required, including targeted testing and surveillance on-farm, the programme will let farmers know, but at this stage the increased frequency of summer bulk tank milk testing, beef surveillance and tracing animals will serve us well.

It was estimated that the cost of M. bovis to farmers would be $1.3 billion over 10 years, and much higher if it became endemic.

Farmers with any concerns can call 0800 00 83 33, email or visit