Pneumonia hits Oregon’s largest bighorn herd along the John Day River

Mycoplasma ovipneumoniae, the pneumonia-causing pathogen M. ovi, has been detected in the John Day River bighorn sheep herd, Oregon’s largest at about 1,000 animals, marking the first known cases in this population. There is no vaccine or treatment; necropsies and lab analyses are underway to determine the strain. Management efforts focus on reducing contact with vectors such as domestic goats and sheep (and concerns over nearby aoudad), with ongoing collaboration among ODFW, tribes, landowners, and other partners. Officials are assessing options to curb transmission, and the public is asked to report any dead or sick bighorn sheep observed in the Day Canyon area.