While brucellosis is not fatal to cattle or humans and symptoms usu- ally go undetected, it is on the federal gov- ernment’s “Most Wanted” list as a livestock disease that brings a lot of rules, research – and anxiety.
Eradicated in the rest of the country, the U.S. Department of Agriculture continues to monitor livestock around Grand Teton National Park and Yellowstone, where elk and wild bison carry the disease.
Under certain conditions it can transmit to cattle, and the USDA’s Animal and Plant Health Inspection Service sets rules for Wyoming, Montana and Idaho, which in turn have their own rules. The “designated surveillance area” of western Wyoming in- cludes Sublette, Lincoln and Sweetwater counties.
All cattle to be shipped outside the DSA have blood drawn and tested by the Wyo- ming State Veterinary Lab to look for indi- cators that might point to brucellosis. The first test looks for a “seropositive” result. Herds with “reactors” are quarantined and movements restricted with more testing until APHIS and state veterinarians get three clean “whole herd tests.”
On Jan. 25 in the Pinedale Library’s Lovatt Room, Pinedale rancher and Rep. Albert Sommers spoke to more than 100 ranchers and agriculture notables about re- cent developments in Sublette cattle herds being tested for brucellosis. The meeting was designed to have each of seven panelists update the public and allow time for questions, answers and comments.
From Oct. 25 through Dec. 11, eight beef cattle herds in Sublette County were investigated due to “non-negative” brucellosis test results after blood tests done just be- fore cattle were shipped showed a possible “positive,” according to State Veterinarian Jim Logan.
Wyoming State Vet Lab tested blood from about 85,000 cattle and domestic bison from across the state last year. Initially tests in all three states until June 2019 were done with the less sensitive “Rapid Automated Presumptive” test, which Logan called “quick and efficient;” it was discontinued due to software issues.
APHIS, state veterinarians and lab biologists then switched to the more sensi- tive Fluorescence Polarization Assay test to
find more cattle in “suspect” and “reactor” ranges; these are called “non-negatives.” With FPA screenings bringing more cattle under the microscope, everyone needed to verify which 2-year-old heifers and cows were actually infected.
On Nov. 14, 2019, the states and APHIS agreed to take FPA-positive animals and test them with the more sensitive Buffered Acidified Plate Antigen test and then Com- plement Fixation test, according to Logan. Last December APHIS approved the new protocol that Wyoming was already using in Sublette County.
This put Sublette ranchers with investigations into limbo not being able to ship cattle and not knowing if their herds would be quarantined.
“All but three of those herds we were able to release from movement restrictions within an average of two and a half weeks,” Logan told the large group gathered on Jan. 25.
Initially, four herds had one “non-negative” animal, three herds had two each and one herd had more than two.
Three Sublette herds are still under quarantine, he added, and one herd could be cleared “pending further serological results,” Logan said.
The only way to prove without a doubt that an animal was infected with brucellosis is to send the carcass to the Wyoming State Vet Lab for a necropsy. Six Sublette cattle took that route.
“Tissue cultures from one animal from Sublette County did grow field strain Brucella abortus,” he said. “Only about 40 percent of serological positive animals yield culture growth of the bacteria.”
Herds under quarantine must have one final test after calving to be released.
“We certainly hope that our quarantined herds can qualify for release in time for spring turnout,” Logan said.
Other counties had “non-negative” results last year, including two investigations in Park County and two quarantined herds. An investigation in Lincoln County and one in Teton County were released.
WLSB Director Steve True said his goal is to market for the state as a whole “to have free and open markets.”
“Our goal in the Designated Surveillance Area is to never have any cattle leave Wyoming with the brucellosis infection,” said WSVL Dr. Brant Schumaker.
Most cattle testing “positive” with the FPA test were negative under the BAPA test, he said. “Hot” heifers and cows in Sublette County were all Bangs-vaccinated and likely had some brucella in their blood.
“False positives create a lot of concern for (ranchers) to market and move their cattle,” a rancher said. If the test results could be returned more quickly, “it would greatly help all the producers.”
Producers should plan ahead for those blood tests well before cattle are shipped so they aren’t blindsided by a “non-negative” result, a Sublette rancher advised.
Should Wyoming Game and Fish go back to its test and removal of seropositive elk at Sublette County feedgrounds?
Director Brian Nesvik said that is not effective long term, takes a lot of work and money, is limited in scope and brings negative publicity. He and Sommers suggested it might be useful in areas without feedgrounds.
Several people commented that communications last fall were poor while herds were tested and led to many rumors. Specific herds and owners are confidential under state law to prevent reputations being wrongly ruined.
“We’re going to fill that vacuum with our own speculations,” Sommers said.
Another rancher offered to use experimental vaccines but Schumacher said local herds provide too small sample sizes.
Also, said Dr. Don Beckett of APHIS, it is the Department of Homeland Security banning use of live brucellosis bacteria. People in the agriculture sector could petition to have that changed, he added.
“Do you think now is the time for all of us combined to make a more united effort to try and address this issue,” asked rancher and Sublette County Commissioner Joel Bousman.
Mike Henn, manager of the cosponsoring Sublette County Conservation District, said a lot of constructive dialogue took place with ideas