The Animal Health Board is taking advantage of the scavenging habits of ferrets to track bovine tuberculosis in western Southland.
There are only two cattle herds still under movement control in the region because of TB infection, compared with 56 herds in 1996.
TBFree Southland chairman Mike O'Brien said ferret trapping plays an important role in protecting cattle and deer herds from Tb-infected wild animals because they indicate whether the disease is present in other wildlife, especially possums, which can spread the disease to livestock.
Mr O'Brien says because ferrets are such good scavengers and are susceptible to the disease, they are very good indicator animals. If postmortem testing finds signs of TB, they will know which particular areas to concentrate on.
"In Southland we have two areas that we know that the disease is still in the wild animal population, and that's in the Hokonui hills and also in the south end of the Takitimu mountains."
He said there have been recent cases of Tb in cattle herds in Western Southland that have been traced back to infected wild animals.
Ferret trapping is taking place along the south eastern side of the Takitimu Range, including the Letham, Opio and the Wether Hill areas. It is due to finish next month.
Possums are responsible for about 70% of new herd infections in Tb risk areas of New Zealand.