Ponderosa pine needles are known to induce late term abortions in cattle. Labdane acids including isocupressic acid (ICA) and agathic acid are the compounds responsible for initiating the abortions. Current research results suggest that an ICA concentration of 0.5% is required for pine needles to be a risk for inducing abortions, while pine needles that contain > 1% ICA pose a significant risk. However, stage of pregnancy, amount consumed, snow cover, temperature and other issues contribute to the overall risk. Research on ponderosa pine needles has demonstrated large variation in the concentrations of the abortifacient compounds, both geographically and seasonally. Concentrations vary from location to location as well as seasonal fluctuations in some areas throughout the year. This variability results in differential potential for pine needle-induced abortions to occur depending upon the location and the time of the year. A number of other trees, including many species of pine, juniper, cypress and cedar contain either isocupressic acid or agathic acid at concentrations sufficient to be a risk for causing abortions in late term pregnant cattle. In this study, we present data that western juniper Juniperus occidentalis trees contain compounds known to be abortifacient in cattle and that consumption of large amounts of bark in the third trimester of gestation can induce abortions. We also examined the geographical variation in the labdane acid content of western juniper trees by measuring the labdane acid content of bark, needles, and berries from western juniper trees from six different locations in Baker County Oregon. The berries had a higher concentration of labdane acids than needles (P<0.001) and bark (P<0.001). Interestingly, bark had a higher concentration of labdane acids than needles (P<0.001). However, there was no difference in the concentrations of labdane acids from location to location for berries (P=0.33), needles (P=0.13), or bark (P=0.15). These results indicate that there is a similar risk for western juniper trees to cause late term abortions in cattle across Baker County Oregon.

Key Words: Juniper-Induced Abortion, Abortifacient, Western Juniper