The last known farm infected with cattle disease Mycoplasma bovis has been cleared of livestock and disinfected, bringing the country's toll of active confirmed properties to zero - again.

New Zealand reached no known cases of the disease in August 2023, before it was detected on a Selwyn farm in September and then its neighbouring property in December.

Clearing the second Selwyn dairy farm took the number of total cleared confirmed properties to 282, while there was still active surveillance on 35 properties.

Six years into the decade-long programme, the Ministry for Primary Industries says the focus will now turn to surveillance of beef, drystock and bulk tank milk testing - important tools in detecting suspected infected properties.

It suggests more cases could be expected in the coming season.

"Due to the nature of the disease and its ability to remain clinically undetected, several years of data, with no new cases of infection, needs to be collected to provide confidence that Mycoplasma bovis is no longer present on New Zealand farms," it says.

"Past programme data tell us we are likely to see more bulk tank milk detect results over autumn and spring."

It urges farmers to keep their National Animal Identification and Tracing (NAIT) records up to date for easy detection if M.bovis positive cases arrive.

First detected in New Zealand in 2017, the disease causes animal welfare and productivity issues such as mastitis (udder infection), pneumonia, arthritis and ill-thrift in calves.

Nearly 180,000 cows have been culled in the programme to date.

-RNZ.