Steer that tested positive for bovine tuberculosis was traced to Potter County seller

State officials believe that a steer that tested positive for bovine tuberculosis came from a feedlot in Potter County before it was sold to DemKota Ranch Beef for slaughter.

State Veterinarian Dustin Oedekoven said there’s still a lot of work to be done in order to identify the steer’s herd of origin.

“We’ve narrowed down the search to 99 source herds, located in Montana, Wyoming, North Dakota, South Dakota and Minnesota. There were many more potential sellers, but we narrowed it down to the most likely herds based on characteristics,” Oedekoven said.

“It’s a lot of work to just narrow it down to where we are at. We are gathering epidemiologic info, and we plan on testing those potential source herds in an effort to find other animals that have been infected,” he said.

Of the 99 potential source herds, 49 are located in South Dakota.

The young, red feedlot steer tested positive for a new strain of bovine tuberculosis during a routine slaughter inspection at DemKota Ranch Beef in June, according to a U.S. Department of Agriculture report to the state’s Animal Industry Board.

“We have been in the process of notifying each of those sellers. These 99 herds were sold through various option markets and then were purchased by dealers. Then they sold them through other auctions,” Oedekoven said.

“I kind of dwell on that a little bit because it has taken some time for us to go through sale records and make a determination,” he said.

Official identification tags are not required for the steer since it was younger than 18 months.

The state Department of Agriculture plans to test 7,000 head of cattle from the potential source herds in the state,” Oedekoven said.

“The test is not really that easy to do. It’s a skin test similar to how people get tested. How we do that in cattle is we run each animal through a shoot, inject a small amount of tuberculin and protein at the soft part of the skin underneath the tail,” he explained.

After two to three days, the injection site is checked to see if the skin is swollen or bumpy at the injection site, which is indicative that the animal may have been previously exposed to tuberculosis.

“We’ll do a second test, and we do expect that three percent of the general cattle population will respond to the first test, then we’ll to additional testing to find out if it’s truly tuberculosis or not.”

Bovine tuberculosis is a chronic, slowly progressive respiratory disease of cattle. Infected animals may transmit infection to other animals in close proximity. Cattle rarely show visible signs of illness, and individual testing of cattle herds is necessary to determine if animals are infected, according to a U.S. Department of Agriculture news release from the state’s Animal Industry Board.

Oedekoven said South Dakota has had other cases of bovine tuberculosis in the last year in Tripp and Harding County. Those cases are unrelated to the feedlot steer case, he said.