Northland farmers have been warned not to be complacent about the cattle disease Mycoplasma bovis.
More than 400 farmers turned out for an information meeting about the disease in Whangarei this morning.
Mycoplasma bovis can cause lameness, abortions and mastitis in cows, but there is no risk to human health from the infection.
MPI officials told the farmers there were no infected properties in the Northland region.
But one farm is operating under a Restricted Place Notice, because it is at high risk of having brought in infected cattle or material.
And four others are under a Notice of Direction - a lesser restriction because they may have received infected animals.
MPI said of the 38 infected properties around the country, 21 were dairy farms, 16 were beef herds, and one was a lifestyle block.
But it said those properties remained a very small percentage of the more than 20,000 farms in the national herd.
There have been 24,500 cattle culled in the fight against Mycoplasma bovis so far.
Northland Federated Farmers president John Blackwell said the disease might yet show itself in the region.
Mr Blackwell said farmers might have unwittingly exposed their animals, because of dubious sale practices.
One farmer bought Waikato calves from a stock agent at New Year, he said, because calves from north of Taupō were immune to bovine anaemia or theileria.
"When the calves started dropping dead from theileria, they then had to ask the stock agent 'what's the problem?' And then they found out they came from some fairly hot areas in Southland.
"And that lead them to the likes of maybe they've brought in Mycoplasma as well."
Mr Blackwell said the livestock industry should have a code of conduct and be subject to the same rules as the real estate industry.