Local ranchers entering calving season have an unanticipated worry to consider after several head of cattle in Harding County, S.D., were recently infected with bovine tuberculosis.
Dr. Dustin Oedekoven, South Dakota’s state veterinarian, told The Pioneer on Tuesday that, while there is no current evidence that tuberculosis (TB) has spread into Bowman County, there is an ongoing investigation to be certain.
Eleven states, including North Dakota, have been notified of cattle having potential contact with the infected herd.
“Most cattle do not show outward clinical signs of tuberculosis, unless in advanced stages,” Oedekoven said. “I would advise producers to be watchful for the general health and welfare of their cattle, as usual.”
According to the USDA, bovine TB is a contagious, chronic bacterial disease caused by Mycobacterium bovis. The infection commonly involves the lungs, but it may spread to other organs. Animals often don’t show signs until the infection has reached an advanced stage.
Mycobacterium bovis is most commonly found in cattle, but can also be found in other animals such as bison, elk, and deer. It can also cause the disease in humans that can affect the lungs, lymph nodes and other parts of the body, according to the U.S. Center for Disease Control.
The precaution stemmed from the discovery earlier this month of 26 head of cattle confirmed with the infection from a Harding County farm, owned by Wayne and Susan Nelson.
The disease was initially discovered in three cows by a Nebraska slaughter plant, which then alerted South Dakota agencies. The cattle, coming from the Nelson farm, appeared healthy but were found to have suspicious-looking lung lesions. Samples were sent out for testing and determined that tuberculosis was present, according to Oedekoven.
It was stated that 13 adjacent herds, approximately 8,000 head of cattle, including the affected herd, would remain under quarantine until testing is complete.
In order for a herd to be taken out of quarantine, the cattle need to be tested and cleared by the state veterinarian’s office.
Because TB is a very slow-moving disease, cattle often don’t ever exhibit signs of the disease, and there is no vaccine or effective treatment for it, according to Oedekoven.
“We luckily have not had to deal with this sort of this in our herd,” said Joy Soreide Kinsey of the Soreide Charolais Ranch in Bowman. “It is an unfortunate situation for any cattle producer.”
A meeting held March 9 in Buffalo, S.D., allowed Oedekoven the opportunity to address the situation with concerned ranchers.
He stated that 11 states are involved as either being home to a source herd or a recipient herd of cattle from the affected herd over the last five years. No state has, as of yet, placed restrictions on cattle from South Dakota or from the affected region.
Until specific lab results are received, Oedekoven couldn’t comment on the origin of the TB strain found in the Nelson’s cattle.
Of interest to the investigation, however, is to determine if deer local to the affected region are carriers of the disease. The South Dakota state veterinarian’s office is working with the South Dakota Game, Fish and Parks staff to decide how best to assess the deer in the area, which could spread the disease.
Cattle in close proximity, such as at a feedlot and those sharing water or feed, would be the most likely to transmit TB to one another. The sun kills the bacteria so the disease is less likely to spread in large numbers in a pasture grazing setting.
It is “possible and likely” that an infected cow would pass the disease to her calf, Oedekoven said.