Oamaru farm latest to test positive for Mycoplasma bovis

Mycoplasma bovis affects both dairy and beef cattle. Photo / File

An Oamaru dairy farm is the latest Otago property to test positive for Mycoplasma bovis as officials struggle to control the spread of the cow disease.

The North Otago farm was one of three South Island farms identified as testing positive for the disease by the Ministry for Primary Industries yesterday.

As well as the dairy farm, the disease was found on an Invercargill beef farm and a sheep and beef farm near Cheviot.

Like all other cases, the three properties were linked to the original group of infected farms through animal movements.

A total of 38 properties have been identified as positive for the disease, the majority in the South Island.

Biosecurity New Zealand chief operations officer Roger Smith told MPs during a briefing at Parliament yesterday the number of farms under regulatory control for the disease had jumped from 130 properties to 290 in the past week.

It was unclear whether it was a one-week blip or whether the disease was reaching epidemic proportions, he said.

Biosecurity New Zealand director of response services Geoff Gwyn said the extent of the disease's spread would become clear in the next six to 12 days.

Officials were still focused on eradicating the disease but Mr Gwyn conceded the focus may have to switch to containment.

"What's happened over the last six days is that long-term management or containment is probably getting a little bit more of our thinking than perhaps it was six days ago."

Primary Industries Minister Damien O'Connor said it was always expected more infected farms would be found.

"[However], officials tell me that the numbers will likely exceed their earlier modelling."

MPI now had 250 staff working on the response to the outbreak which was first discovered more than 300 days ago.