Current Edition

current edition

Brucellosis

Boulder – Wyoming won’t lose its “Class Free” status as the result of a brucellosis-infected cow discovered at a Nebraska slaughter plant earlier this month. The cow, along with 17 others from the same herd, was sold via a livestock barn direct to slaughter.
    Wyoming State Veterinarian Walt Cook told attendees at the Sept. 16 Governor’s Brucellosis Task Force Meeting in Boulder, Wyo. that the Nebraska plant collected the backtag and eartags from the cow at slaughter. The lab in Kansas that processed the cow’s blood sample, however, misplaced those tags. While Cook said the cow was likely infected, additional testing can’t be carried out in the absence of a carcass. “The carcass is gone by this time and we can’t do additional tests,” said Cook. “It is possible this is a false reaction, but I think that’s pretty unlikely because the titer was really high.”
    The cow’s herd mates, numbering 1,600, are grazing federal allotments until early November. At that time the index herd, along with two herds that share the allotment, will be bled. As a result of the common allotment, Cook said the USDA Animal and Plant Health Inspection Service (APHIS) is treating all three herds as if they are one.
    A smaller portion of the herd from which the cow originated is grazing in the Boulder area and were to be be tested on Friday.
    USDA APHIS Area Vet In Charge Bret Combs said Wyoming’s Class Free brucellosis status hinges on a second case within a two-year period of the infected herd recently discovered at Daniel. “Presently we’ve got one infected herd,” said Combs. “If the herd at Bondurant turns out to be an infected it’s an automatic.” At that time the federal government would take the steps to downgrade Wyoming from “Class Free” to “Class A” as it relates to brucellosis. “If that herd tests negative we’re at one and we’ve got whatever time is left on the two-year period.”
    Cook also told the group that the infection might be correlated to a neighbor who doesn’t own cattle and had intentionally fed elk since the 1970s, an activity Wyoming law currently allows. Last year, following an elk injuring one of his horses, the individual decided he no longer wanted to feed the elk. Game and Fish has since been working with him to remove elk from his property during the winter months. Cook said the case points to the dangers of feeding elk and to the dangers of suddenly shutting down such feeding operations.
    With support from the Wyoming Livestock Board and the Wyoming Game and Fish, legislation will be pursued at the upcoming legislative session to make the intentional feeding of elk illegal. Earlier unsuccessful efforts have more generally addressed wildlife, but by narrowing the legislation supporters hope to have better success.
    As leaders from the WLSB and APHIS left the Tuesday meeting they were destined for a two-day conference in Denver at which the rules and regulations governing brucellosis were to be addressed. Among the sought-after changes will be a more workable “test out” option for producers. Requirements that a herd be depopulated to avoid a state losing its Class Free status also lack support in the more modern scenario of wildlife to livestock transmission.
    Task Force members also voted to pursue $200,000 from the Wyoming Legislature to support vaccine research. Ranchers say inadequate vaccines are now one of the biggest challenges in combating the disease. Private companies have expressed little interest in pursuing such research. By week’s end Governor Dave Freudenthal had endorsed the budget request that would be handled via the University of Wyoming College of Agriculture.
    Jennifer Womack is managing editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

Casper – USDA’s Animal and Plant Health Inspection Service (APHIS) has released a concept paper outlining potential updates to the national rules and regulations it operates by when a case of brucellosis is discovered in cattle.
    APHIS officials unveiled their proposal for the future of brucellosis management during the recent U.S. Animal Health Association (USAHA) meeting. A nine-page document explaining the proposal accompanied the announcement and is available for download at www.wylr.net.
    APHIS calls for creation of a designated “National Brucellosis Elimination Zone” or “NBEZ,” in the Greater Yellowstone Area (GYA) encompassing portions of Idaho, Montana and Wyoming. “The establishment of this zone,” says the agency, “would facilitate the elimination of brucellosis from livestock and provide clear, consistent control and surveillance guidance to livestock producers in the NBEZ, while simultaneously allowing the balance of the United States to be considered free of bovine brucellosis.”
    Implementing the plan will require a risk assessment to determine the area’s boundaries. Those boundaries would be fluid and adjusted with a change in risk factors.
    Livestock producers in the area would be asked to take part in a risk assessment addressing topics like the presence of elk, management practices and biosecurity efforts. “The risk tool,” says the USDA, “will provide a standardized method for producers and animal health officials to define a herd’s risk of acquiring brucellosis, identify needed mitigation to reduce risk, conduct surveillance to assure early detection, and allow movement with confidence of a herd’s freedom from brucellosis.”
    APHIS’s document says, “Livestock producers may have the opportunity to improve their herds’ risk score by adopting mitigation strategies associated with the identified risk factors. Producers within the NBEZ will use their herd risk scores to choose which herds they add to or allow to mingle with their herds, under guidelines similar to existing herd certification programs. However, a herd’s risk status will be raised if producers add from or mix with herds of a higher risk status.”
    APHIS says what it describes as a tiered structure will allow states to target their resources at areas where there’s an identified risk. “Herd level surveillance will include movement testing, investigations of abortion events, and serological testing of herds. Again, the amount and frequency of herd testing required will depend on the herd-risk status.”
    Wildlife is also addressed in the NBEZ document with APHIS writing, “The NBEZ concept presented here is only part of a successful approach to brucellosis elimination in the GYA. Implementation of the NBEZ requires a concurrent planning effort with many wildlife agencies including entities in the GYA.”
    Asked about plan specifics APHIS Veterinary Services (APHIS-VS) spokesperson Lyndsay Griffin says, “This initial proposal is just a concept paper so states have an ability to influence the plan and how it’s implemented.” She says they want to get the states’ reactions before engaging in the deeper planning process. “We’re waiting for the states to give us feedback on if they like the plan.”
    APHIS says the changes could take many months to complete with a timeline from the document accompanying this article. “Prior to publishing the official rule that will develop the zone, APHIS-VS intends to work in close partnership with the GYA States to establish the zone boundaries and concomitant standardized surveillance activities, mitigations, and movement controls….APHIS will begin working immediately to establish zone boundaries following stakeholder and partner acceptance in the NBEZ concept.”
    APHIS recognizes an increased cost for the agency, but says an accurate estimate cannot be provided until NBEZ boundaries are determined and mitigation strategies developed. “Additional funds in the GYA States will be necessary,” says APHIS. “These funds will support additional field and technical personnel, vehicles, laboratory activities, travel, supplies, administrative and analytical support, producer incentives, and vaccination, among other things.”
    “The overall goal is to declare the entire U.S. free of brucellosis with exception of this one region with the eventual goal of eliminating it totally,” says Griffin.
    The National Brucellosis Elimination Zone Proposal can be found on-line at www.wylr.net. It’s located on the home page in the upper right hand corner. Jennifer Womack is managing editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..
Cheyenne – A Daniel rancher whose herd was found to be infected with brucellosis earlier this summer has until Aug. 29 to depopulate his herd or Wyoming will lose its brucellosis free status.
    According to a mid-July memo from Wyoming State Veterinarian Walt Cook, two timeline extension requests were submitted to the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS). The first request, asking for more time to test adjacent herds, was granted. That gives the state until Oct. 31 to complete testing on neighboring herds.
    The second request, which would have allowed the producer until after this fall’s tests are complete to make his decision, was denied. If another brucellosis-infected animal is found this fall Wyoming would lose its class free status regardless of the Daniel producer’s decision.
    “He is most likely going to test out, keep testing and removing positives until his herd is declared clean,” says Cook. “He may change his mind before Aug. 29, but I doubt it very much. He will be testing his herd again next week and again late August. He will be analyzing those results to make up his mind 100 percent.”
    Unless the producer changes his mind Wyoming will lose its brucellosis-free status, but Cook says he’s not yet sure what that will mean for livestock producers across Wyoming. “I am sure there will be some statewide testing requirement. But, we are hoping we can limit that to breeding animals only and do more in-depth testing in the risk area,” says Cook.
    Sublette County producers have expressed their support for the Daniel rancher’s decision not to depopulate his herd. WLSB officials, in earlier editions of the Roundup, have said it’s time to update federal regulations surrounding brucellosis to better reflect present-day situations. The regulations were written at a time when cattle to cattle transmission was the largest risk pertaining to brucellosis. With the wildlife to livestock transmission risk in northwest Wyoming, depopulating a cattle herd does little to nothing to mitigate disease risk. Participants in recent online poll at www.wylr.net agreed, with nearly all respondents saying it’s time to update the federal regulations.
    Two neighboring herds have been tested with no cattle testing positive for brucellosis. Additional herds will be tested this fall when they come off summer pasture. As additional testing gets underway on the producer’s ranch and others, Cook says the state and federal government do pay for the testing. “Personnel from both agencies take the samples and we pay for the actual testing at the state vet lab.”
    Jennifer Womack is managing editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

In addition to the existing case in Park County, brucellosis has been confirmed in a privately owned bison herd in Park County, and is suspected in a cattle herd in Sublette County.
Preliminary tests Nov. 23 indicate possible brucellosis in one Sublette County cow tested at the Riverton Livestock Auction. By the next day, the Wyoming State Veterinary Lab confirmed a second blood test as “hot.” The suspect herd is under quarantine, and was blood-tested Nov. 28, by Wyoming Livestock Board (WLSB) veterinarian Chris Strang. Adjacent and contact herds are being notified, and the cow has been slaughtered and tissue samples sent for culture testing. Results of the blood and culture tests are expected within the first week of December.
While the infection outbreak in the bison herd is not related to the brucellosis case in the Park County cattle herd discovered in late October, it is within the Wyoming Designated Surveillance Area (DSA), and appears to also be caused by exposure to infected free-ranging elk.  
“The (bison) herd owner was selling 12 heifers by private sale for out of state slaughter,” said Wyoming Assistant State Veterinarian Bob Meyer at a public meeting in Meeteetse Nov. 30. “The herd owner wanted to make sure they were clean from brucellosis, and had them tested Nov. 10. Out of the 12 heifers, there were two reactors. We euthanized one of the heifers and took blood and tissue samples that were cultured by the Wyoming State Veterinary Lab and the National Vet Services Lab. On Nov. 24 that heifer was confirmed to have Brucella abortus, Biovar 1, the field strain of brucellosis.”      
The WLSB’s state veterinarians began testing the herd, and out of 253 bison, 18 more reactors were discovered.     
USDA-APHIS designated the herd as an “affected herd,” and the WLSB quarantined it and one adjacent herd. Meyer anticipates testing to be completed on the affected herd and adjacent herds by Dec. 10. Epidemiologic interviews are underway to determine the extent of this outbreak. The WLSB is referring to the affected bison herd as Herd 2, while the case discovered in the Park County cattle in October is referred to as Herd 1.
Meyer says there are about 1,400 head of bison in the entire herd, and he is working with the owners to test the remainder of the herd and develop a herd management plan.  
“There are two contact herds for sure, and there may be one or two more,” says Meyer.  “No cattle have gotten in with these bison, and the bison haven’t gotten out, but there are cattle that share a boundary. We’ve tested all the cattle herds that were related to first herd, and we have a good start on some of the herds that are adjacent to second herd. Some of the herds that are adjacent to the second herd are also adjacent to the first herd, and they’ve already been tested and were negative. So far, we haven’t found any cows in an adjacent herd that could explain the infection of those herds. The preliminary epidemiology points to infected elk as probably being the source of these infections.”   
Over the past year and a half, USDA-APHIS has coordinated with all state veterinarians to develop changes to the federal brucellosis rules. The state veterinarians of Wyoming, Idaho and Montana have had considerable input into these discussions. The new or “Interim Rule” provides the state and affected herd owners with some flexibility in how situations are handled.  
Wyoming State Veterinarian Jim Logan said in a recent news release, “We expect to have occasional brucellosis cases in our DSA since we have the last remaining reservoir of Brucella abortus in this country in the Greater Yellowstone Area. Livestock producers take many precautions to prevent exposure to wildlife, but there are some situations that even the best management cannot always avoid.”
As Logan is out of the office on medical leave, Meyer has taken the lead in the brucellosis cases.
The WLSB encourages producers not to panic, as the affected herds should be able to “test-out,” or slaughter only confirmed brucellosis infected animals, rather than slaughter their entire herds.
Echo Renner is a field editor for the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..


Cheyenne - The Wyoming Livestock Board (WLSB) has received an official letter stating the USDA’s Animal and Plant Health Inspection Service (APHIS) has granted an extension for the depopulation of a herd in western Wyoming from which cattle have tested positive for brucellosis.
    The Daniel producer who owns the herd will test his cattle again on Aug. 25 and 26, after which the samples will be delivered to the state vet lab in Laramie. Wyoming Assistant State Veterinarian Jim Logan says results should be known by Aug. 28.
    “According to the extension, after he’s informed of the results of the testing he has two working days to make a decision about depopulation,” says Logan. For example, if he gets the results on a Friday he’ll have until the next Tuesday to make a decision. The original deadline for depopulation was Aug. 29, after which Wyoming would have lost its brucellosis-free status.
    If the producer does decide to depopulate his herd, he’ll have 30 days following his decision day to complete the action. If not, he’ll stay under quarantine until there are at least three full-herd negative tests taken no less than 30 days apart. The last one has to be at least six months later, if not more, and has to be after calving.
    “In the second test we took in July, 30 days after the first test, we found seven more positive, so it’s very possible that we could have some more, but it’s also very possible we could not,” explains Logan. “The reason we do these tests at least 30 days apart is because of the variation in the incubation period in any given animal. Although they all may have been exposed at the same time, they may not all test positive at the same time.”
    Logan says sometimes brucellosis can incubate for longer than a year, but that anywhere from two weeks to a few months is typical. “In rare cases there have been animals exposed as calves that haven’t shown up positive on a blood test for several years,” he says, explaining that Latent Heifer Syndrome is a mystery in that it incubates but doesn’t show up on a test.
    “Now we’re waiting on the producer and trying not to put any more pressure on him than he already has,” notes Logan. “It’s a big weight to have the status of the entire state on your shoulders.”
    In a mid-August meeting the WLSB adopted changes to the Chapter 2 Brucellosis Rules that expand the area in which brucellosis testing is required. Due to increased elk seroprevelance in western Park County, the WLSB is concerned about the possibility of the spread of brucellosis from elk to cattle in that area. Emergency rules that would go into effect immediately have been sent to Gov. Freudenthal.
    The emergency rules will be in effect for 120 days, during which the Chapter 2 rules will be out for informal comment for 30 days, followed by a formal comment period of 45 days. A draft of the proposed rules can be obtained from the WLSB at 307-777-7515, or on the WLSB website at http://wlsb.state.wy.us.
    Public meetings will be held to discuss the proposed rules in Pinedale at the Pinedale High School Auditorium, 101 E. Hennick Street, on Sept. 23rd at 7 p.m.; in Cody at the Park County Extension Office, EOC Room, Courthouse, 1002 Sheridan Ave., on Sept. 24 at 7 p.m.; and in Douglas at the Fairgrounds Cafeteria on Sept. 25 at 7 p.m.
    Christy Hemken is assistant editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..