Update on Bovine Tb Trace to Wyoming from a Tb Infected Colorado Herd
On behalf of Dr. Logan, please see below.
Update on Bovine Tb Trace to Wyoming from a Tb Infected
Colorado Herd A few weeks ago we were notified of a Tb trace to Wyoming
from a Tb infected herd in Colorado. The original trace from Colorado involved 10 Holstein steers.
These 10 steers were mixed with 67 other Holstein steers at the livestock auction market. The group of 77 was then added to another 91 Holstein steers in a pasture in Wyoming,
making a total group of 168 Holstein steers. None of these animals were identified to the farm/ranch of origin with a brand or official
identification, and they were not required to be since our Chapter 8 Import
rules do not require official ID on imported steers.
Because we could not identify the original 10 head of
steers from the Colorado Tb infected premises, we had to test the entire
group of 168 steers.
Additionally, this group of Tb exposed animals had fence line contact with 245 beef steers in an adjoining pasture, so
that group of animals also had to be tested, making a total of 413
animals tested. A USDA-APHIS-VS team of Wyoming, South Dakota, Colorado,
and Montana personnel completed the caudal fold testing (CFT) on
Thursday, November 18 (our WLSB personnel were Brucellosis testing in Park
County). There was one CFT responder in the Holstein group and one CFT
responder in the beef cattle group from the adjoining pasture. Dr. Meyer will accompany the Holstein steer to slaughter today to check for Tb
lesions and collect tissue samples.
Dr. Kizer (APHIS) will collect blood from the responder in the beef group for Gamma Interferon testing
to determine if that animal is a true Tb infected animal.
This situation is significant for three reasons:
1. It shows Wyoming's vulnerability to Tb from imported
cattle. This has probably been our closest call with the disease
exposing Wyoming cattle and we are lucky there were not more contact
herds, especially breeding cattle;
2. It exhibits the good cooperative working relationship
we have in Wyoming between WLSB and USDA-APHIS to accomplish this
testing and epidemiology in rapid response to these situations; and
3. It provides an example of the value of official ID for
imported cattle. Had the
original ten steers from Colorado been officially identified to the herd of origin, we may only have needed
to test those ten head instead of the entire group of 168 Holstein
steers. Certainly once a Tb responder was found, it necessitated testing
every animal he was with or had fence line contact with, but if no
responders had been found in the original ten steers traced, there would not
have been any further testing required.
Dr. Meyer will provide further updates on this situation
IF either of the steers shows bona fide evidence of Tb infection.
Betsy Milek [mailto:bmilek@state.wy.us]
Administrative Assistant
State Veterinarian's Office
Wyoming Livestock Board
610 Fairground Road
Riverton, WY 82501
307-857-4140
307-857-6380 (fax)
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