Protecting Bighorn Sheep in the Okanogan-Wenatchee National Forest

March 26, 2021: Advocates for the West completed briefing for a Preliminary Injunction to halt domestic sheep grazing in the Okanogan-Wenatchee National Forest pending the outcome of our case. The Preliminary Injunction request cites the potential for catastrophic outcomes to nearly half of the wild bighorn in Washington state and that the Forest Service has failed to plan for or require separation between domestic sheep and bighorns to prevent disease outbreaks among the bighorns.

November 30, 2020: Advocates for the West filed suit in federal court claiming the Okanogan-Wenatchee National Forest is placing bighorn sheep at high risk of livestock disease outbreaks by authorizing domestic sheep grazing in the vicinity of bighorn herds. Representing WildEarth Guardians and Western Watersheds Project, we assert that the Okanogan-Wenatchee National Forest has known of the high risk that domestic sheep grazing poses to bighorn sheep for at least a decade, yet has authorized grazing anyway.

Domestic sheep carry a pathogen that, when transmitted to bighorn sheep, causes deadly pneumonia in bighorns and reduces lamb survival rates for years. The pathogen—known as Mycoplasma ovipneumoniae—is especially deadly because bighorns and domestic sheep are mutually attracted to each other. Once disease is in a bighorn herd, it can cause low lamb survival for a decade, and members of that herd can easily transmit the disease to nearby bighorn herds. There is no cure or vaccine. Our lawsuit alleges that the Okanogan-Wenatchee National Forest continued to authorize domestic sheep grazing despite knowing about the high risk to bighorns as far back as 2010.