Tb outbreak affects West Coast herds

Photo / File

Herds which have been free of bovine tuberculosis (Tb) for decades are caught up in a fresh outbreak at Hari Hari.

Nine herds in the Hari Hari and Waitaha catchments are dealing with infections, after the first infected herd was diagnosed in July 2020.

In a statement, Ospri Tb Free NZ said the area had had sporadic infections over the past 20 years, and the last infected herd was 2019, after contact with infected wildlife.

"It is important to note, Hari Hari has always been deemed a vector risk area, meaning wildlife is thought to be maintaining Tb in their population - hence the ongoing possum control programme in the area. The infection in cattle herds is driven by Tb infection recycling in wildlife," Ospri said.

It planned to increase spending on possum control programmes to $9 million over the next five years.

The 2021-22 pest control programme is underway. Ground control completed around December is now being followed up with aerial 1080 poisoning in the One One and Ianthe areas.

Ospri has also implemented a movement control area requiring annual Tb testing of all animals aged over three months, and pre-movement testing of stock moving to grazing or for sale.

It also does blood tests on animals from infected herds and any animal that reacts to the skin test in clear status herds, to help with the removal of infected animals.

"As part of our response plan we are providing NAIT educational support and advice for farmers to enable them to meet their NAIT obligations to support disease management."

Six of those have completed a first clear whole herd test.

Reducing possum numbers and controlling Tb would also lead to a drop in infections in other species such as deer, Ospri said.

Hari Hari dairy farmer Mary Molloy, of Farmers Against Ten Eighty, is unconvinced.

"Nothing about this makes sense," she said.

Until this outbreak, just one or two farms in the wider area were dealing with infection.

"None of the rest of the farms have had issues for 20 to 30 years. Now it's just one or two (infected) stock per farm,"Molloy said.

According to Ospri, 10 of the 36 infected herds in New Zealand are on the West Coast and 17 in Hawke's Bay.