Ensuring Northland possums don't get bovine TB is a key component in protecting the region's economy.
There would be huge implications if the tuberculosis (TB) infection found in an Awanui dairy herd last week got into the possum population, TBfree Northland Committee chairman Neil MacMillan, of Okaihau, said yesterday.
If that happened the disease could threaten farms which are the mainstay of the regional economy. Northland's 296,000 dairy cattle earned $641 million in 2011/12, when the region's 403,000 beef cattle made $125 million.
Mr MacMillan said the Far North would have a grass surplus this year and he warned farmers planning to sell grazing to make sure any southern cattle coming north were from TB-free areas.
TB infections in two dairy herds in the Awanui area in 2009 were believed to have arrived on the backs of trucks, he said.
Apart from a pocket at the Kaipara South Head, the area north of Auckland had been free of bovine TB. The disease had been horrific in southern cattle herds up to the 1970s when a definitive test to identify it was developed.
The test cut the incidence of TB so the Government trimmed funding to combat the disease, but bumped it back up in 1994 when there were 1694 infected herds in New Zealand. The disease is present in about 70 herds nationally, with the West Coast the main hotspot.
Cattle infection by wild animals was a major fear for Northland.
Mr MacMillan said an infected wild pig caught at Kaeo in 1996 had been attributed to a lifestyle farmer who had brought it north from the Wairarapa.
A Northland deer recovery unit was set up in 1997 with funding from the Animal Health Board (AHB), Department of Conservation and Northland Regional Council to deal with Sika deer which misguided hunters were believed to have released into the Russell State Forest.
Recovery unit hunters have also dealt with about 60 animals annually which escaped from Northland deer farms. The region had 4000 deer behind wire in 2011/12.
Some Northland farmers complain about the cost of the disease control programme, but Mr MacMillan said most appreciated their costs would be higher if the region lost its TB-free status.
"I can recall only one instance where a farmer near Mangonui wouldn't co-operate with the AHB," he said. "A court order dealt with the situation and his deer were eventually shot."