Pine needle abortion biomarker detected in bovine fetal fluids

Authors: SNIDER, DOUGLAS - Iowa State University; Gardner, Dale; JANKE, BRUCE - Iowa State University; ENSLEY, STEVEN - Iowa State University

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2014
Publication Date: 12/22/2014
Publication URL: http://handle.nal.usda.gov/10113/62769
Citation: Snider, D.B., Gardner, D.R., Janke, B.H., Ensley, S.M. 2014. Pine needle abortion biomarker detected in bovine fetal fluids. Journal of Veterinary Diagnostic Investigation. 27(1):74-79.

Interpretive Summary: Pine needle abortion is known to occur in free-range cattle caused by the consumption of pine needles. Previously diagnoses were dependent on a case history of possible pine needle consumption and clinical signs of abortions including the birth of a premature calf and retention of fetal membranes in the dam. In some cases, the metabolites of the pine needle toxin, isocupressic acid, could be detected in the serum of the dam if taken within a few days of pine needle consumption. In this study, alternate tissues were examined for detection of isocupressic acid metabolites in two aborted fetuses that were presented for analysis following the abortion of several calves from cows grazing a native pasture area in western Nebraska. Analysis of fetal fluids (stomach and thoracic fluids) were found to be positive for a isocupressic acid metabolite known as tetrahydroagathic acid. The current investigaiton clearly demonstrates the usefulness of submitting fetal tissue for analysis in possible pine needle abortion cases.

Technical Abstract: Pine needle abortion is a naturally occurring condition in free-range cattle caused by the consumption of pine needles from select species of cypress, juniper, pine, and spruce trees. Confirmatory diagnosis of pine needle abortion has previously relied on a combined case history of pine needle consumption and detection of isocupressic acid in a sample from the dam. Stable metabolites of isocupressic acid include agathic acid, dihydroagathic acid, and tetrahydroagathic acid, which have been shown to be present in the serum of mature animals for a few days following consumption of pine needles. As maternal serum is infrequently submitted for diagnosis of cattle abortions, a diagnostic assay capable of confirming isocupressic acid exposure in other matrices would be desirable. To the authors' knowledge, no previous investigations have indicated whether these stable metabolites of isocupressic acid cross the placenta or are detectable in fetal tissues. Therefore, the presence of agathic acid, dihydroagathic acid, and tetrahydroagathic acid was evaluated using gas chromatography-mass spectroscopy on fetal thoracic fluid and stomach contents collected from 2 aborted bovine fetuses with a recent herd history of pine needle consumption by the dams and a subsequent abortion outbreak in the herd. Only tetrahydroagathic acid was detected in the fetal thoracic fluid and fetal stomach contents. The current study encourages diagnosticians to collect fetal thoracle fluids to permit the detection of tetrahydroagathic acid in cases of suspected pine needle abortion.