New Zealand officials have announced plans to kill around 150,000 cows in an attempt to eradicate a strain of disease-causing bacteria.
"We do believe we are taking it on at a point that it is possible to eradicate and more than 99 percent of farms don't have it and we want to protect them from having it".
Mycoplasma bovis, bacteria that can cause mastitis, pneumonia, and other diseases in cattle, was first identified in the country in July and has since spread to at least 37 farms. The bacteria is not harmful to humans and does not pose a threat to food safety.
"This is a tough call", said Prime Minister Jacinda Ardern.
"This is a tough time, and the pain and anguish [affected farmers] are going to go through is really ugly", she said. It has been found on about 40 farms so far, but 192 farms are likely to be involved in the culling.
The government said it would bear around two-thirds of the cost, while farmers and the cattle industry will pay the rest.
New Zealand is the world's largest exporter of dairy products, and produces 3% of the world's milk.
Mycoplasma bovis was first detected in New Zealand in July past year, and manifests in mastitis in cows, severe pneumonia, ear infections and other symptoms.
The full cost of eradication over 10 years is projected to be $886 million.
Around 24,000 cows have already been killed in recent months. Some experts fear the decision will come at a huge cost.
Farming is vital to the economy in New Zealand, whose isolation has helped protect it from some diseases which affect herds elsewhere.
Katie Milne, president of the advocacy group Federated Farmers, said they would try to ensure that farmers received the financial and emotional support they required.
No country has managed to eradicate Mycoplasma bovis so far.
Officials say they expect to know by the end of the year whether the eradication plan is working.