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Decertifying the herd


In December, the state of Wyoming discovered 29 cattle infected with brucellosis on Donald Jensen’s ranch in Sublette County. Those cattle were slaughtered and the disease was thought to be contained.

But last week, six cattle from the same herd turned up in a Worland, Wyo., feedlot. According to the letter of the law, two infected herds have now been found in Wyoming within the last two years, and that means the state will lose its brucellosis-free status, conferred by the federal Animal and Plant Health Inspection Service (APHIS).

Losing that status—held by Wyoming since 1985—would place the state alongside Texas and Missouri as the only states not classified brucellosis-free.

Currently, cattle are the primary suspects for transmission of the disease, though testing by the Wyoming Board of Livestock has yet to produce evidence of cattle-to-cattle transmission.

“Right now they’re trying to test all contact herds to dispel the possibility that it was another bovine,” Wyoming Game & Fish biologist Brandon Scurlock said. “If they do exhaust all possibilities, they will focus on elk transmission.”

Unlike Montana, Wyoming has 22 state-run wintertime feedgrounds for elk, including the Muddy Creek feedground located near Jensen’s ranch. Elk that concentrate on feedgrounds tend to have much higher rates of brucellosis infection. Brucellosis, contracted by contact with infected aborted fetuses, spreads more easily within large congregations of animals, simply because of the greater numbers that can come into contact with infected material.

Scurlock last conducted brucellosis tests on Muddy Creek in 1997. At that time, he found an infection rate of 29 percent. Other feedgrounds in the state have produced rates as high as 50 percent. Near Yellowstone’s northern border in Montana, where elk are naturally dispersed, the rate is only 4 percent.

If it turns out that elk are responsible for transmitting the disease, the revelation could lead to several possible outcomes, including a test-and-slaughter program such as Montana uses for bison, or an end to feedgrounds altogether in Wyoming.

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