LANDER - A Wyoming rancher has been given at least another month to decide if he'll comply with a federal request to slaughter his brucellosis-infected cattle herd, a state official said Wednesday.

The reprieve could help make the thorny decision a bit more clear-cut for the rancher, State Veterinarian Walt Cook said.

The federal government has agreed to extend its deadline for a Daniel-area stockgrower to "depopulate" his breeding cattle, and he should have until late September or early October to comply with the feds' request, Cook said.

The original slaughter deadline was Aug. 29.

"We received official approval of the extension, but it's got some conditions on it," Cook said. "Basically, he's testing his herd again next week, Monday and Tuesday. When he gets the results, he has two days to decide if he wants to depopulate, then he'll be given an extra 30 days to complete the slaughter."

Because it could take a week or more from the testing date before the rancher receives the lab results, he probably won't know if more of his animals have tested positive until the first week of September. That means he could have until the first week of October to comply with the federal deadline, Cook said.

If the rancher, whose identity is protected by state law, fails to slaughter his breeding animals by the new deadline, the entire state will lose its "brucellosis-free" market status for cattle.

To date, 36 of the rancher's 650-head herd have tested positive for the bacterial disease.

At this point only his cattle have tested positive for brucellosis. But if animals from another cattle operation in the Cowboy State test positive within a two-year period, the state will automatically lose its brucellosis-free status.

Brucellosis can cause cattle and other hoofed animals to abort. And because it causes undulant fever in humans, it has been the target of a federal eradication program for more than 70 years.

Cook asked the U.S. Department of Agriculture last month to extend the slaughter deadline from Aug. 29 to later this fall, in order to give the state the opportunity to test the remaining 11 herds that have possibly come into contact with the infected herd. This would then allow the rancher to make a more informed decision, Cook argued.

Instead of slaughtering all of his breeding animals, the Daniel rancher has been leaning toward an optional test-and-slaughter program, whereby he could eventually make his quarantined herd officially brucellosis-free again, by killing only those animals with the disease.

The rancher has been favoring this alternative, rather than depopulating his entire herd, in order to preserve a genetic strain of black Angus cattle he's worked hard to develop, area ranchers and state officials have told the Star-Tribune.

But Cook indicated that the results of next week's testing could change the rancher's mind.

"If he has a lot of animals that test positive, he'll probably depopulate the herd," Cook said. "But if he has one or two, he'll have to make a decision at that time."

The optional testing program would take at least one year to complete, but federal rules say the rest of the state would unavoidably lose its brucellosis-free status in the meantime, even if no other Wyoming herds test positive for the disease.

Two of the 13 herds that potentially mingled with the infected herd have been tested so far, and both have come back negative for brucellosis. The rest of the "contact" herds are out on summer range.

Charles Price, another Daniel-area rancher, recently explained that the stockgrower with the infected herd has possibly nothing to gain, economically, from maintaining the state's brucellosis-free classification - and he has potentially quite a lot to lose from slaughtering his remaining breeding cattle.

Lynda Vickrey, also of Daniel, who raises cattle with her husband inside the state's four-county brucellosis "surveillance" area, said in essence they're already operating under the restrictions that would be levied statewide if Wyoming were to lose its brucellosis-free status.

At last week's meeting of the Wyoming Livestock Board, the body approved "emergency rules" to be submitted to Gov. Dave Freudenthal, which would include the western part of Park County in the state's surveillance area for brucellosis, Cook said.

The emergency rules will be delivered to Freudenthal by the end of this week, and he'll likely make a decision about them within two weeks, he said.

Representatives of the governor's office were not immediately available for comment Wednesday afternoon.

Contact Chris Merrill at (307) 267-6722 or chris.merrill@trib.com.