Bovine tuberculosis has been discovered in a north Taranaki dairy herd.
The Animal Health Board was investigating the cause of the TB infection and has prepared a plan to manage the disease on the farm, near Inglewood.
Cattle can move off the farm only with the board's permission, board Northern North Island regional co-ordinator Frank Pavitt, of Hamilton, said.
The disease was detected last month in a cull cow and soon afterwards in another cow during routine testing.
The 220-cow herd would be tested every three months and tests would also be undertaken as soon as possible on six neighbouring herds if they were untested this dairy season.
One other Taranaki herd has TB. In 2009, a cluster of South Taranaki herds tested positive to the disease, and one still with the infection is close to clearance. The source was never found.
Taranaki herds are tested for the disease every three years in a programme funded by levies on slaughtered animals and milksolids production.
Mr Pavitt said milk pasteurisation and New Zealand's strong meat inspection programme stopped TB entering the food chain, but animals identified with the disease were withdrawn immediately from a herd.
Sources of TB in domestic cattle were possums and ferrets, wild pigs or deer brought to an area for a recreational hunting resource, stock "off the back of the truck", or undetected infection in a herd.
Mr Pavitt said TB had a big impact on the options and finances of a herd owner, who could dispose of empty or low-producing cows only by selling them for slaughter, receiving only 65 per cent of market value. Owning an infected herd could have a stigma, even when there was no fault.
Farmers with an infected herd usually used their experience to raise others' awareness, he said.
TBfree Taranaki chairman Donald McIntyre, of Tariki, said owning an infected herd was stressful because it brought extra costs and disrupted farm routines, often for a year or more while the disease was eliminated.
The infection was a stark reminder TB still posed a threat to farmed cattle and deer in Taranaki.
Farmers should check the animal status declaration forms of all stock arriving on their properties.
Taranaki cattle and deer owners should register their herds, meet test requirements, correctly tag stock and complete animal status declaration stock movement forms, he said.
Taranaki Federated Farmers dairy chairman Derek Gibson said the infection's discovery showed the importance of the testing programme. "Farmers have to be aware the disease is still sitting out there."
Farmers wanting more information about managing their TB risk can contact the Animal Health Board on 0800 482 4636 or at tbfree.org.nz.
- Taranaki Daily News
Is it time for authorities to introduce tougher penalties for poaching?Related story: Booby traps for poachers cost farmers