A case of milkweed poisoning in cattle in Colorado

Authors: WALCK, RAYE - Colorado State University; WEBB, BRETT - Colorado State University; ENSLEY, STEVE - Kansas State University; Cook, Daniel

Submitted to: Poisonous Plant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2025
Publication Date: 3/28/2025
Citation: Walck, R., Webb, B., Ensley, S., Cook, D. 2025. A case of milkweed poisoning in cattle in Colorado. Poisonous Plant Research. 8:31-36. https://doi.org/10.26077/9c06-d94e.
DOI: https://doi.org/10.26077/9c06-d94e

Interpretive Summary: Milkweeds, Asclepias spp., are herbaceous perennials of the Apocyanaceae family. Milkweeds contain several cardiac glycosides, cardenolides, that are toxic. Clinical signs associated with milkweed toxicity are generalized weakness, difficulty in breathing, rapid weak pulse, bloating, violent spasms, paralysis, and death. Here we report a clinical case of milkweed toxicity in cattle due to contaminated hay. Clinical signs observed in the poisoned animals were consistent with cardenolide toxicity. Milkweed was detected in the rumen contents of the poisoned cow using DNA metabarcoding. In summary, multiple lines of corroborative evidence were used to make the diagnoses of milkweed poisoning in this case.

Technical Abstract: Milkweeds, Asclepias spp., are herbaceous perennials of the Apocyanaceae family. Milkweeds contain several cardiac glycosides, cardenolides, that are toxic. Clinical signs associated with milkweed toxicity are generalized weakness, difficulty in breathing, rapid weak pulse, bloating, violent spasms, paralysis, and death. Here we report a clinical case of milkweed toxicity in cattle due to contaminated hay. Clinical signs observed in the poisoned animals were consistent with cardenolide toxicity. Milkweed was detected in the rumen contents of the poisoned cow using DNA metabarcoding. In summary, multiple lines of corroborative evidence were used to make the diagnoses of milkweed poisoning in this case.