Federal and state sharpshooters have begun culling free-ranging deer in the bovine tuberculosis management area, the state Department of Natural Resources said Tuesday.

The DNR and U.S. Department of Agriculture sharpshooters will continue work on the ground through the first part of April, aided by up to two weeks by an aerial deer removal operation slated for mid-March, the DNR said, adding that ground operations may continue if warranted.

The effort replicates that done last winter in an effort to reduce the number of free-ranging white-tailed deer in northwest Beltrami County and Roseau County in the area with cattle herds discovered with bovine TB.

"Our continued goal is complete eradication of bovine TB from Minnesota," Ed Boggess, deputy director with the DNR Division of Fish and Wildlife, said in a statement. "The state's aggressive approach remains the best chance of relatively short-term actions achieving long-term benefits for wild deer and livestock in Minnesota."

DNR helicopter surveys completed in early February show that there are about 660 deer, an estimated 4.1 deer per square mile, in the 164-square-mile bovine TB core area. Last year, similar helicopter surveys in the same area showed 800 deer, about five deer per square mile.

In February through April 2008, ground and aerial sharpshooters took 937 deer from the core area. Six animals tested positive for bovine TB, bringing the total number of infected deer to 24 since surveillance efforts began in 2005., the DNR said.

Also, landowners harvested 125 deer throughout the landowner/tenant shooting zone last year. None of those deer were positive for bovine TB. Final results should be available by mid-summer for the 1,246 hunter-harvested deer that that the DNR sampled during the 2008 fall hunting seasons, the DNR said.

"The good news is that none of last year's hunter-harvested deer showed any obvious clinical signs of bovine TB, and the prevalence of disease remains low and is restricted to a small area," said Dr. Michelle Carstensen, DNR wildlife health program coordinator. "However, we obtained few samples from the bovine TB core area and there are still many deer in that area. We need to keep the pressure on these deer to reduce the risk of this disease becoming established in the herd."

Every infected deer was born during or before 2005, and has been taken within just 5 miles of a cluster of four bovine TB-infected cattle farms, the DNR said.

Meanwhile, the state Board of Animal Health reports that it had 46 herd buyout contracts from cattle producers in the bovine TB management area who agreed to remove or slaughter about 6,200 head of cattle by Jan. 31.

The 2008 Legislature strengthened the state's efforts to eradicate bovine TB from beef cattle with a buyout program and by creating an intensive bovine TB management area.

The program led to the discovery of positive animals in one buyout herd in Beltrami County. "This positive finding validates the entire buyout program," said Minnesota Bovine TB Coordinator Joe Martin. "We have found positive herds in this area before, and we knew it might happen again. By removing cattle from the management zone and working to decrease the deer population, we are carrying out our strategy of eradicating the disease."

Producers that remain in the cattle business or store feedstuffs were required to complete a risk assessment to determine whether the operation's feed and forage crops were adequately protected from free-ranging white-tailed deer, the Board of Animal Health said.

The board required 27 producers in the management zone to fence livestock, feed storage and winter feeding areas. The 2008 legislation provided for a cost-share assistance of 90 percent of the fence cost, up to $75,000. All of the required fencing is complete, with more than 71,000 feet of fence installed.

"Livestock producers in northern Minnesota have worked tirelessly to complete the required fencing, cattle load outs, and herd testing," said Minnesota State Veterinarian Dr. Bill Hartmann. "Across the state of Minnesota, more than half a million animals have been tested for bovine TB since the disease was first discovered in Minnesota in 2005. We are indebted to the producers and veterinarians of Minnesota for their cooperation and commitment to eradicating this disease."

As a result of the intensive effort to control bovine TB in the management zone, the U.S. Department of Agriculture rated the rest of the state as TB-Free, the least restrictive category for the movement of beef cattle across state lines.

The DNR said that people interested in obtaining field-dressed carcasses of deer that were sharpshooter-shot that show no signs of infection can place their name on a waiting list by contacting Thief Lake Wildlife Management office at 218-222-3747.