The use of earwax to determine livestock exposure to teratogenic lupine

Authors: Stonecipher, Clinton - Clint; Lee, Stephen; Welch, Kevin; VALLES, KRISTIAN - Utah State University; Cook, Daniel

Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2024
Publication Date: 7/30/2024
Citation: Stonecipher, C.A., Lee, S.T., Welch, K.D., Valles, K.R., Cook, D. 2024. The use of earwax to determine livestock exposure to teratogenic lupine. Toxicon. 248: Article 108053. https://doi.org/10.1016/j.toxicon.2024.108053.
DOI: https://doi.org/10.1016/j.toxicon.2024.108053

Interpretive Summary: Lupines are common plant species on western U.S. rangelands. Several lupine species containing toxins that can cause crooked calves when pregnant cows consume the lupine between 40-100 days of gestation. Previous research has shown that lupine toxins can be detected in earwax of cattle grazing lupine infested rangelands. Our hypothesis is that earwax can used to determine if cattle have consumed toxins from multiple lupine species. Two lupine species were present on a ranch in east-central Idaho that has experienced multiple years of crooked calves. Earwax was collected from 69 pregnant cows that had grazed on the ranch with multiple lupine species. Analysis of the earwax determined that cows were consuming more of one lupine species than the other. Earwax was determined to be a good non-invasive sample to aid in the diagnosis of cattle that have consumed lupine and appears, in this case, to be a good diagnostic tool to differentiate between more than on lupine species that may be causing the crooked calves.

Technical Abstract: Lupines (Lupinus spp.) are a common plant species on western U.S. rangelands with several lupine species containing alkaloids that can be toxic and/or teratogenic to livestock. In North America, more than 150 lupine species are recognized with some ranches or grazing allotments containing multiple species. One or more of these lupine species may contain alkaloids that are teratogenic to cattle. Previous work has shown that lupine alkaloids can be detected in earwax of cattle grazing lupine infested rangelands. Our hypothesis is that earwax can be used to determine if cattle have been exposed to teratogenic alkaloids from multiple lupine species. Two lupine species, L. sericeus and L. polyphyllus, were present on a rangeland in east-central Idaho. The teratogen, anagyrine, was detected in L. sericeus and the teratogen, ammodendrine, was detected in L. polyphyllus plants collected on this rangeland. In this study, earwax was collected from 69 pregnant cows that had previously grazed a rangeland containing two different lupine species containing alkaloids that cause CCS. Anagyrine was detected in the earwax of all 69 cows sampled. Ammodendrine, was detected in the earwax of 28 of the 69 cows sampled. Earwax is a good non-invasive sample to aid in the diagnosis of cattle that have consumed lupine and does appear, in this case, to be a good diagnostic tool to differentiate between more than one lupine species that may be the cause of CCS. Concentrations of anagyrine or ammodendrine did not correlate with the incidence of CCS.