Evaluation of the Seasonal and Annual Abortifacient Risk of Western Juniper Trees on Oregon Rangelands

•Western juniper trees can cause late term abortions in cattle, similar to ponderosa pine trees.•Results from this study demonstrate that there is no difference in the labdane acid (the abortifacient compounds) content of western juniper trees throughout the year, or from year to year.•Consequently the abortifacient risk of western juniper trees should not vary throughout the year, or from year to year.•Producers who winter cattle in rangelands with western juniper trees should take similar precautions to prevent late term abortions as they would with ponderosa pine trees.