Volume 4, Number 17 - July 22, 2004
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Infected herd had been in Sublette County
Wyoming State Veterinarian Dr. Jim Logan told members of the Wyoming Brucellosis Coordination Team that the Teton County cattle herd that was recently found to have brucellosis had been in Sublette County sometime last year.
Logan said that the epidemiological investigation continues, so he isn't sure exactly where the cattle were, or for how long. That means that it hasn't been determined if more Sublette County cattle will have to be bled for brucellosis testing.
Dr. Bret Combs of the USDA Animal and Plant Health Inspection Service added that while he's not sure exactly where the cattle were when they were in Sublette County, the general location was somewhere between Pinedale and Daniel.
Logan said the new brucellosis case, known as the Teton County index herd, has been known for about a month now. He said that brucellosis was detected in this herd after routine testing for interstate movement of the herd occurred in early July. The herd was bound for summer pasture in Idaho; 105 head of adult cows were tested on June 16, with the result being one reactor titer.
"That animal was a Montana-origin cow that was 11 years old," Logan said. The cow had been in Wyoming since 1999, when it was brought with other cattle into the index herd. The cow had tested negative on a previous blood test.
The index herd had finished calving, with 90 calves on the ground and about 15 open cows. The reactor cow had given birth to a healthy calf in April, Logan said, adding that the calf is still in the herd.
The reactor cow had been vaccinated in 1993 or 1994 with Strain 19 vaccine, so false positive reactions aren't unexpected. When the reactor titer result occurred, state officials contacted the herd owner to discuss the situation.
On June 22, the cow was slaughtered in the field by a federal veterinarian along with the ranch's private veterinarian. Numerous tissue samples were harvested and on July 8, the federal laboratory reported heavy growth of the 5R4 field strain of brucella on numerous tissue samples submitted from the infected cow.
Logan said that the strength of the titer and culture growth indicate it probably is a very recent exposure, possibly late this spring. The cow was probably exposed pretty late in her pregnancy, he said.
Logan said as soon as the state knew that the cow was a positive reactor, he quarantined that herd as well as a contact herd, although the contact herd is actually on public land grazing allotments on the Bridger-Teton National Forest and in Grand Teton National Park. Since this herd was already on its summer range, and its doubtful that all the animals could be gathered for testing without missing some at this point, state officials have decided to test the herd when it comes off the allotments in the fall, Logan said.
The index herd had wintered with the contact herd since last November.
On July 15 Dr. Mark Stewart of APHIS retested the 104 head from the index herd, finding one "weak suspect."
The herd owner is now examining his options, Logan said, acknowledging these really aren't options: either long-term quarantine with frequent testing and no movement of the herd from private property, or depopulation of the entire herd.
Combs said that the owner is leaning toward depopulating. With it costing the herd owner $1,000 per week to feed hay to the quarantined herd, he can't afford to continue that in the long-term, Combs said.
"He's in a little bit of a box as to what his options are," Combs said, adding that APHIS is ready to appraise the herd to prepare for an indemnity payment if the herd owner does decide to go with depopulation.
As for how the herd contracted brucellosis, Logan said it's too soon to know. The index herd had been around elk fairly frequently, including coming in close contact with the Dog Creek elk feedground, Logan said, but to his knowledge it did not have contact with bison. However, the quarantined contact herd was known to have commingled with bison.
"Certainly we will be doing some contact herd testing this fall," Logan said.
The contact herd had been subject to numerous brucellosis tests in the last 10 years, Logan said.
"The contact herd may be the most-tested herd in Wyoming," Logan said.
House District 22 Representative Monte Olsen of Daniel keyed in on the concept of having a quarantined cattle herd on public land.
He questioned, "What's the public perception going to be?" Olsen suggested that Logan's office is "going to get beat up real bad" by having a quarantined herd on public land and not being tested.
Logan said he'll try to continue to get the point across that the public land involved is known to have brucellosis-infected wildlife and the herd at issue is the contact herd that will be tested this fall.
"I don't think we are at any more risk than we've ever been," Logan said.
"I still think that the bottom line here is that we have tolerated infected wildlife in certain areas where we now have a herd that might - might - have been exposed," Logan said.
Monday's meeting of the Wyoming Brucellosis Coordination Team in the Sublette County Library in Pinedale earlier this week was the group's sixth. The group, appointed by Governor Dave Freudenthal, has spent its first several months of regular meetings focused on reducing the risk of brucellosis in cattle and on cattle transmission issues, working to develop a toolbox of best management practices and draft recommendations that once finalized, will become part of a report back to the governor.
With much of the groundwork laid on the cattle issues, the task force changed its focus, turning Monday to human health issues and regulatory response. The group will hold its next meeting in late August in Lander.
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