Over 20,000 infected cattle to be slaughtered across NZ in our biggest ever agricultural cull

More than 22,000 cattle will be slaughtered at all properties infected by Mycoplasma bovis in a dramatic effort underway to stop the spread of the devastating cow disease.

MPI says it's the only way to fully eradicate cow disease Mycoplasma bovis from the 28 properties it's been detected on. Source: 1 NEWS

It's the biggest cull of its type in New Zealand's history and officials say it's the only way to fully eradicate the disease from the 28 properties.

The decision to slaughter over 22,000 cows hasn't been an easy one.

"This is a very significant cull. It's the first time it's happened in New Zealand agriculture. We hope we don't have to do this again," said Damien O'Connor, Agriculture and Biosecurity Minister.

It's hoped the cull will completely eradicate Mycoplasma bovis.

The Ministry for Primary Industries says it has been left with little choice after 113,000 tests showed the disease wasn't widespread yet.

"It couldn't have happened any earlier as we needed to understand how widespread the disease was. If it was endemic in New Zealand we'd be looking at other options," said Geoff Gwynn of MPI.

Six infected properties have already been cleared of nearly 5,000 stock after the disease was identified in July last year. 

And all farmers on the 22 remaining properties, mainly in the South Island,  will be compensated.

"They are compensated for any verifiable loss as a result of MPI exercising powers. And clearly we're using Biosecurity Act powers to order the cull of the animals," Mr Gwynn said.

This will be a wake up call for everyone at every level in the dairy and livestock industry. - Damien O'Connor, Agriculture and Biosecurity Minister

Dairy New Zealand was quick to voice its support for the decision to cull, saying it gives certainty for dairy farmers and it's extremely positive the disease isn't widespread.   

But Mr O'Connor says the financial damage has already been done. 

"The potential cost to the industry either way -  that is in controlling this or eradicating or leaving it go - is in the hundred of millions of dollars. What we've got to do is try and prevent this happening again and get onto it more quickly," he said. 

Mr O'Connor says there needs to be a major shake-up when it comes to farm biosecurity, with farmers needing to keep better records  when stock are moved.

"This will be a wake up call for everyone at every level in the dairy and livestock industry." 

Nobody wants to see a cull of this scale happen again.