Parsons,* C1., Welch K.D.2
1.Agriculture Extension Agent, Oregon State University Cooperative Extension Service, Baker County, Baker City, OR. 97814.
2.USDA Agricultural Research Service, Poisonous Plant Research Laboratory, 1150 E 1400 N, Logan, UT 84341
Since the early 1900s livestock producers have had problems with pine needle abortion. Ponderosa pine (Pinus ponderosa) needles from trees on open rangelands of the western United States and Canada have a long history of causing abortions in cattle. Pine needle related abortions occur most frequently in the last trimester of gestation. Affected cattle often have difficult calving (dystocia), incomplete cervical dilation, weak uterine contractions and retained fetal membranes. The combination of these clinical findings, early parturition, dystocia, and retained placental membranes have been used to classify a pine needle abortion. Current management recommendations indicate that any tree with 0.5% isocupressic acid (ICA), or higher is a risk for inducing abortions in late-term pregnant cattle. During the fall/winter of 2009/2010 a study was conducted to analyze the ICA content of Western Juniper (WJ) (Juniperus occidentalis), and any impacts of feeding WJ bark to late term pregnant beef cattle. Preliminary results showed that WJ bark contained (0.46%) slightly less than the 0.5% threshold. The feeding trial resulted in two of six (1/3) of the cows aborting their fetus within five days of initiation of treatment and exhibiting classical pine needle abortion type symptoms. Although ICA concentrations were slightly below reported thresholds and only 1/3 of exposed cattle aborted their fetus, in a real world situation very few ranchers could economically survive the loss of 1/3 of their calf crop. We feel that additional research is required to more fully understand the impacts of consumption of WJ bark.