Clinical, pathological and toxicological characterization of Salvia relexa (lance-leaf sage) poisoning in cattle fed contaminated hay

Authors: Panter, Kip; Stegelmeier, Bryan; Gardner, Dale; Stonecipher, Clinton - Clint; Lee, Stephen; KITCHEN, DON - Colorado State University; BRACKETT, ADELINE - Brackett Veterinary Services; DAVIS, CHARLIE - Colorado State University

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2020
Publication Date: 3/10/2021
Citation: Panter, K.E., Stegelmeier, B.L., Gardner, D.R., Stonecipher, C.A., Lee, S.T., Kitchen, D., Brackett, A., Davis, C. 2021. Clinical, pathological and toxicological characterization of Salvia relexa (lance-leaf sage) poisoning in cattle fed contaminated hay. Journal of Veterinary Diagnostic Investigation. 33(3):537-547. https://doi.org/10.1177/1040638721995784.
DOI: https://doi.org/10.1177/1040638721995784

Interpretive Summary: Nearly 500 beef cattle were poisoned and 165 died after they were fed alfalfa hay contaminated with Salvia reflexa (lance-leaf sage). Most died within 48 hours with smaller numbers dying 3 to 10 days later. Many other poisoned animals slowly recovered. Signs of poisoning included feed refusal, depression, lethargy followed by sternal then lateral recumbency, bellowing, colic, and death. A few cattle that survived 4-5 days developed neurologic disease with aberrant behavior, aggression, icterus, apparent blindness, exhaustion and death. After the first day, the contaminated hay was removed. Three fatally poisoned cattle were examined and found to have severe liver necrosis. The toxicity of the hay was confirmed by feeding to cattle and the plant toxins were identified using a mouse bioassay guided chemical fractionation process. Four toxic diterpenoid hepatotoxins were identified. S. reflexa and diterpenoid toxicity was confirmed in goats. These finding are the first reported in North America to implicate S. reflexa as a hepatotoxic plant that could fatally poison livestock.

Technical Abstract: Approximately 500 beef cattle were poisoned and 165 died after they were fed alfalfa hay contaminated with Salvia reflexa (lance-leaf sage). Most died within 48 hours with smaller numbers dying 3 to 10 days later. Many other poisoned animals slowly recovered. Signs of poisoning included feed refusal, depression, lethargy followed by sternal then lateral recumbency, bellowing, colic, and death. A few cattle that survived 4-5 days developed neurologic disease with aberrant behavior, aggression, icterus, apparent blindness, exhaustion and death. After the first day, the contaminated hay was removed. Three fatally poisoned cattle were necropsied. Gross findings included swollen, dark, mottled livers that had a prominent nutmeg-like lobular pattern on cut section. Histologically the fatally poisoned animals had severe centrilobular to pan lobular hepatic necrosis characterized by marked hepatocyte swelling, degeneration and necrosis with centrilobular aggregates of fibrin, cellular debris and pools of erythrocytes. Subsequent serum biochemical and evaluation of hepatic biopsies of non-fatally poisoned animals demonstrated that most cattle that had access to the contaminated hay were affected to some degree. The toxicity of the hay was confirmed in cattle after which the toxic contaminant was identified as S. reflexa. The toxic components of the hay and subsequently S. reflexa were also identified using a mouse bioassay guided chemical fractionation process. Four toxic diterpenoid hepatotoxins were identified. S. reflexa and diterpenoid toxicity was confirmed in goats. These finding are the first reported in North America to implicate S. reflexa as a hepatotoxic plant that could fatally poison livestock.