Bovine Tuberculosis (TB) was identified in three beef cows during routine slaughter inspection by USDA Food Safety Inspection Service inspectors at two Nebraska slaughter plants in February, 2017. The cows had been in feedlots in Nebraska and South Dakota since November, 2016. Market records were used to identify the herd of origin in Harding County (northwestern South Dakota), which was tested by state and federal animal health officials, revealing additional infected animals.
No cattle remain on the index ranch in Harding County. Test negative animals were sent to inspected slaughter, revealing two additional infected cows. Cleaning and disinfection of conveyances, water tanks, and other potential sources of contamination will be completed. It is anticipated that the ranch may begin restocking soon.
One cow in an adjacent herd was found to be infected. This cow originated from the index herd and was moved to the adjacent herd in May, 2015. The remainder of this herd is quarantined, has tested negative and will undergo a second herd test in late May. No evidence of infection was found during testing of over 8,000 cattle in 12 other adjacent herds.
State and federal animal health officials continue to track cattle using sales records, official animal identification records, and certificates of veterinary inspection to identify animals that may have originated in the index herd and may now be in other herds.
One Butte County cow purchased from the index herd through a livestock auction market in May, 2016, was found to be infected. The remainder of this herd has tested negative and will undergo a second herd test in 60 days. All neighboring herds have been tested with negative results and the quarantines have been released.
Molecular characterization of Mycobacterium bovis, the causative agent of bovine tuberculosis, from the infected animals has identified this strain as being very similar to a strain identified in Queretaro, Mexico in 1997. This strain is new to the U.S., and it's pathway of introduction into the Harding County herd is as of yet unknown.
|Number of Herds Identified with Infected Cows||3|
|Number of adjacent Herds Quarantined||1|
|Number of adjacent Herds Released from Quarantine||19|
|Number of Trace Out Investigation Herds in SD||105|
|Number of Trace Out States||12: ND, MT, WY, CO, NE, KS, OK, MN, IA, MO, AR, TX|
|Total Cattle Tested in SD (June 16, 2017)||10,893|
Test results from the National Veterinary Services laboratories for bovine tuberculosis were negative for all white-tailed deer, mule deer, pronghorn, coyote, raccoon sampled from western Harding County. The surveillance and sampling operation of certain wildlife species was conducted in response to cattle testing positive for TB in early 2017. The salvageable meat that was processed will now be delivered to local food pantries through Feeding South Dakota. South Dakota Department of Game, Fish and Parks staff, in consultation with the South Dakota Animal Industry Board, will soon begin discussions for long-term surveillance of TB in wildlife.