Listen: Encouraging progress in fight against M. bovis

There is encouraging progress in the battle against Mycoplasma bovis as the bulk milk testing program nears its final stage, says the Ministry for Primary Industries.

MPI's Intelligence Manager for the M.bovis response Dr Alix Barclay told The Country's Jamie Mackay bulk milk testing so far had shown only three additional properties infected with the cattle disease, and they were all connected to farms already affected.

Read more about Mycoplasma bovis here.

Barclay predicted the majority of the bulk milk testing would be "done and dusted", by December, and although the results would be "very useful", this survey alone wouldn't answer whether Mycoplasma bovis had been eradicated.

"I don't think the milk survey will answer that question for us ... there are other surveys as well, like our calf survey and our national mastitis work that will also contribute to that."

There was only a single incursion of Mycoplasma bovis and Barclay said MPI still didn't know how it entered New Zealand.

"We are continuing to investigate ... but we must remember that this appears to have happened a year or 18 months before we were aware of it. So it's going to be quite hard to investigate back there."