Wyoming veterinarian urges ranchers to test their herds for bovine TB
Although bovine tuberculosis has not been discovered in Wyoming, ranchers here should be protecting their herds against the deadly disease.
TB has been controlled in the U.S. but it has not been eliminated totally,” said Wyoming State Assistant Veterinarian Bob Meyer.
Meyer told ranchers at the Range Beef Cow Symposium in Cheyenne that bovine TB concerns him because the investigation in Tripp County, South Dakota, is still ongoing. Bovine TB was confirmed in a South Dakota herd on Nov. 17 and the cattle are under quarantine. This is the second case of bovine TB in the state this year. A Harding County herd was depopulated due to testing positive for TB in April. To read more about the Tripp County bovine TB case, see pages 60-63 in this week’s magazine.
The herd in Tripp County was a closed herd except for the buying of bulls. Meyer said. And, the TB from the herd in Tripp County is from a different source than the TB in Harding County.
Meyer urged cattle producers to test animals prior to purchase and to test again in 60 days before comingling them with their herds. “If I was buying replacement cattle from South Dakota I would have them tested, whether it is required in Wyoming or not,” he said.
He also suggested that producers keep a closed herd to reduce risk and to know their sources if they are putting together groups of heifers.
TRACING THE DISEASE
Because TB is most often detected when cull cows are slaughtered, he encouraged producers to ID animals and to keep good records.
“Animal ID and good records can help regulatory personnel more quickly trace animals and determine exposure,” he said. Without ID, tracking becomes complicated and time-consuming thereby enabling the disease to spread to other herds.”
Meyer also warned about commingling roping and rodeo cattle with the herd.
“Occasionally, we will see on our kill floors cattle with TB, mostly from a roping or rodeo cow,” he said.
When asked if cattle could contract the disease from deer, Meyer said it was unlikely in the U.S., except for a reservoir in the upper peninsula of Michigan, which at one time had spread to a herd in neighboring Wisconsin but has since been isolated in Michigan. “Four to five herds in Michigan get infected each year from deer,” Meyer said. Minnesota also had a reservoir at one time but it was eliminated, he said.
Cattle from Mexico also can be at risk, which is challenging because the U.S. brings in about 1 million steers a year for feeding.
Recreational cattle and dairy cows should also be suspect.
In the event that TB is found in someone’s herd, it will most likely be quarantined until the source is found and depopulated.
“The best test we have to day is the skin test,” he said. “ But it’s not 100 percent at finding infected animals. About 15 percent of animals tested won’t be caught. Some cows just don’t respond to the test that’s why we have to depopulate the herd.”
The Range Beef Cow Symposium was held Nov. 28-30 at the Little America Resort and Convention Center in Cheyenne. The event is sponsored by the Cooperative Extension Service and animal science departments of the University of Wyoming, South Dakota State University, Colorado State University and the University of Nebraska. The biennial symposium rotates among Colorado, western Nebraska, western South Dakota and Wyoming. Attendees listen to various speakers during the day and in the evening Bull Sessions allow producers to ask specific questions of speakers and to discuss the day’s topics more in depth.
For more information on the Range Beef Cow Symposium, visit http://www.rangebeefcow.com. ❖