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ARS Home » Pacific West Area » Logan, Utah » Poisonous Plant Research » Research » Publications at this Location » Publication #283624
Title: Evaluation of the seasonal and annual abortifacient risk of western juniper trees on Oregon rangelands

Author
item Welch, Kevin
item Cook, Daniel
item Gardner, Dale
item PARSONS, CORY - Oregon State University
item Pfister, James
item Panter, Kip

Submitted to: Rangelands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2013
Publication Date: 2/1/2013
Citation: Welch, K.D., Cook, D., Gardner, D.R., Parsons, C., Pfister, J.A., Panter, K.E. 2013. A comparison of the abortifacient risk of western juniper trees in Oregon. Rangelands. 37(4):139-143. DOI: 10.1016/j.rala.2015.05.005.

Interpretive Summary: Western juniper trees appear to be a risk to induce late-term abortions in cattle. However, this risk is not well characterized and it is unclear how much variation there is in the abortifacient compounds in western juniper trees. Thus, the objective of this study was to collect samples of bark, needles, and berries from western juniper trees across the state of Oregon to determine how much variation there is in the abortifacient compounds in western juniper trees so as to better understand the variation in potential abortion risk. Results presented in this study from over 400 trees from over 35 locations across the state of Oregon suggest western juniper trees in all areas present an abortion risk in pregnant cattle. The abortifacient compounds are found in bark, needles, and berries, with bark posing the most significant risk. There is substantial tree to tree variation, with some trees having extremely high concentrations of the abortifacient compounds and thus posing a significant risk to cause abortions in cattle. Consequently, cattle producers who winter cattle in pastures with western juniper trees should take similar precautions to prevent late term abortions as they would with ponderosa pine trees.

Technical Abstract: Needles from ponderosa pine (Pinus ponderosa) trees are known to cause late term abortions in cattle. Recently, there have been several reports of abortion rates of 10-15% within cattle herds in Oregon after cattle were pastured in areas with abundant western juniper trees (Juniperus occidentalis). In each of these instances, there was no ponderosa pine, or other trees previously known to contain ICA, found in these areas, while there was clear visual evidence that cattle had consumed bark and needles from western juniper trees. The bark, needles, and berries from western juniper trees contain labdane acids similar to ponderosa pine needles, albeit in lower concentrations. A pilot study indicated that the bark from western juniper trees could induce abortions in cattle. Consequently, western juniper trees appear to be a risk to induce late-term abortions in cattle. However, this risk is not well characterized and it is unclear how much variation there is in the abortifacient compounds in western juniper trees. Previous research has shown that there can be significant variation in the ICA content of ponderosa pine needles from location to location and over time. Thus, the objective of this study was to collect samples of bark, needles, and berries from western juniper trees across the state of Oregon to determine how much variation there is in the abortifacient compounds in western juniper trees so as to better understand the variation in potential abortion risk. Results presented in this study from over 400 trees from over 35 locations across the state of Oregon suggest western juniper trees in all areas present an abortion risk in pregnant cattle. The abortifacient compounds are found in bark, needles, and berries, with bark posing the most significant risk. There is substantial tree to tree variation, with some trees having extremely high concentrations of the abortifacient compounds and thus posing a significant risk to cause abortions in cattle. Consequently, cattle producers who winter cattle in pastures with western juniper trees should take similar precautions to prevent late term abortions as they would with ponderosa pine trees.