WDFW anticipating having to kill 15 bighorn sheep to prevent deadly pneumonia outbreak

Yellowstone rams catch disease causing unsightly mouth sores

ELLENSBURG, Wash. — The Washington Department of Fish and Wildlife is anticipating having to kill 15 bighorn sheep to prevent a deadly pneumonia outbreak among the herd.

Wildlife biologists are taking steps this week to assess whether a deadly pathogen has infected the Quilomene herd in Kittitas County. The herd is one of the largest in the state, with between 220 and 250 sheep.

An off-duty Kittitas sheriff’s deputy observed a domestic ewe with seven bighorn rams in a remote area of the Ginkgo Petrified Forest State Park earlier this month. With permission from the ewe’s owner, it was removed and tested at Washington State University’s veterinary diagnostic laboratory, where it was confirmed the animal was carrying mycoplasma bacteria. This bacteria leads to fatal pneumonia in bighorn sheep.

“At this time, we know the ewe was with wild bighorns in the most southern portion of the herd’s range, where approximately 50 bighorns are located,” said Mike Livingston, WDFW Region 3 Director. “What we have to find out is whether any of the wild sheep have contracted the disease from her. It’s an unfortunate situation, but the operation, which will primarily target rams, should have minimal effect on the overall population.”

WDFW anticipates having to lethally remove 15 sheep and test 10 to 15 additional animals using non-lethal means, to assess if the herd is infected.

Biologists said the disease can reduce the survival rate of lambs born to surviving animals for many years after the initial outbreak. The breeding season has already started and Livingston said the department will have to move quickly.

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