Western juniper-induced abortions in beef cattle

Authors: Welch, Kevin; Gardner, Dale; Panter, Kip; Stegelmeier, Bryan; PARSONS, CORY - Oregon State University; Pfister, James; Cook, Daniel

Submitted to: International Journal of Poisonous Plant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2010
Publication Date: 11/15/2011
Citation: Welch, K.D., Gardner, D.R., Panter, K.E., Stegelmeier, B.L., Parsons, C., Pfister, J.A., Cook, D. 2011. Western juniper-induced abortions in beef cattle. International Journal of Poisonous Plant Research. 1(1):72-9.

Interpretive Summary: It has been known for many years that pine needle induced abortion is a significant economic problem for ranchers, estimated at $4.5 million annually . It has been demonstrated that labdane acids including isocupressic acid and agathic acid are the compounds responsible for initiating the abortions. Recent research efforts have demonstrated that a large number of trees including many species of pine, juniper and cedar trees, contain either ICA or AA at concentrations sufficient to be a risk for causing abortions in late term cattle. During the late 1990’s and early 2000’s many ranchers in Baker County, Oregon were using western juniper trees in riparian restoration projects. There have been reports by several ranchers of 10-15% of their herds aborting after being pastured in areas that contain large amounts of downed western juniper trees. Ponderosa pine and other trees known to contain ICA were not found in the areas in which these abortions occurred. However, there was clear visual evidence that the cattle had been eating the bark of the downed western juniper trees. Therefore, samples of western juniper needles, berries, and bark were analyzed for labdane acid content. Preliminary analyses indicated that the bark of western juniper trees has a fairly high concentration of labdane acids (~ 1.0 %). Consequently, the objective of this study was to determine if the bark from western juniper trees can induce abortions in cattle. The results from this study demonstrate that the bark from western juniper trees can induce abortions in cattle. Consequently, livestock producers should be aware of the potential for western juniper trees to induce abortions in late-term pregnant cattle, especially if grazing conditions deteriorate so that cattle are compelled to eat juniper.

Technical Abstract: Objective—To determine if the bark from western juniper (Juniperus occidentalis) will induce late term abortions in cattle. Animals—6 two-year-old Angus heifers. Procedures—Bark from western juniper trees was collected, dried, and finely ground. Pregnant cows were dosed starting on day 250 of gestation with 2.3 kg of ground plant material twice daily for 10 days or until abortions occurred. Blood was collected each morning prior to treatment for determination of the serum concentration of labdane acids. Results—Western juniper bark used in this study contained approximately 0.7% labdane acids, on a dry weight basis, including isocupressic acid (0.025%), agathic acid (0.43%), imbricatoloic acid (0.15%), and dihydroagathic acid (0.05%). Two of the six cows aborted 4-5 days after the start of the treatment. Both cows had retained placental membranes. The remaining 4 cows calved at full term (26-31 days after the start of treatment) and had no complications nor retained placental membranes. Conclusions and Clinical Relevance—Results from this study indicated that the bark from western juniper trees contains compounds known to be abortifacient in cattle and that consumption of large amounts of bark by cattle in the third trimester of gestation may induce abortions. Although the risk of abortion from eating western juniper bark appears to be less than that of ponderosa pine needles, livestock producers should be aware of this potential. Caution should be used when pregnant cattle, during late gestation, are allowed access to downed western juniper trees.