Abortifacient effects of lodgepole pine (Pinus contorta) and common juniper (Juniperus communis) on cattle

Lodgepole pine (Pinus contorta) and common juniper (Juniperus communis) contain high levels of isocupressic acid that has been identified as the abortifacient component of ponderosa pine needles in cattle. Therefore, the abortifacient potential of P contorta and J communis needles was tested in feeding trials with pregnant cattle. Cows (2 groups of 2 each) were fed by gavage 4.5-5.5 kg/d ground dry needles from either P contorta or J communis starting on gestation day 250. Isocupressic acid (ICA) levels in P contorta needles and J communis plant material were 0.8 and 2.0% (dry weight) respectively. Cows fed P contorta received a daily dose of 62-78 mg ICA/kg body weight and aborted after 8 and 10 d. The 2 cows fed J communis received a daily dose of 190 and 245 mg ICA/kg body weight and aborted after 3 and 4 days respectively. All cows retained fetal membranes and had classical clinical signs of pine needle-induced abortion. Pinus ponderosa, P contorta, J communis, and Cupressus macrocarpa samples were also analyzed for the presence of myristate and laurate esters of 1,14-tetradecanediol and 1,12-dodecanediol. These lipid like compounds of P ponderosa have potent vasoconstrictive activity in a placentome perfusion assay and are proposed as possible abortifacients in cattle. Concentration of the vasoactive lipids were 0.028% (P ponderosa), 0.023% (P contorta), 0.001% (J communis), and none detected (C macrocarpa). It was concluded that these compounds are not required for the plant material to be abortifacient in cattle.