|Stonecipher, Clinton - Clint|
|Green, Benedict - Ben|
Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2017
Publication Date: 1/30/2017
Citation: Welch, K.D., Stonecipher, C.A., Green, B.T., Gardner, D.R., Cook, D., Pfister, J.A. 2017. Administering multiple doses of a non N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-containing tall larkspur (Delphinium occidentale) to cattle. Toxicon. 128:46-49. doi: 10.1016/j.toxicon.2017.01.020.
Interpretive Summary: Larkspurs (Delphinium spp.) are a serious toxic plant problem in the western U.S. The toxicity of larkspur plants is due to alkaloids which occur as two chemical structural types, the MSAL-type and the non MSAL-type. Delphinium occidentale has been shown to have two different alkaloid chemotypes, one which contains the MSAL-type alkaloids and one that does not. The chemotype which contains the MSAL-type alkaloids is more toxic to cattle. However, it is unclear what risk there is for cattle that graze in rangelands where the non MSAL chemotype is found. In this study, we performed a dose-response analysis wherein multiple doses of non MSAL-containing tall larkspur were administered to steers at 12 h intervals, with the objective to identify how much larkspur cattle can consume daily without adverse effects. The results from this study suggest that cattle can consume enough non MSAL-containing tall larkspur to be poisoned. Based upon the data and calculations/extrapolations, at least two thirds of a cow’s diet would have to include a non MSAL-containing larkspur for cattle to become poisoned. Therefore, there is a risk for cattle to be poisoned by the non MSAL-containing larkspurs, albeit much lower than that for MSAL-containing larkspurs. However, it should be kept in mind that there is a potential for larkspur toxicities to be exacerbated by the co-consumption of other poisonous plants.
Technical Abstract: Larkspurs (Delphinium spp.) are a serious toxic plant problem for cattle in western North America. There are two chemotypes in the tall larkspur Delphinium occidentale, a more toxic chemotype and a less toxic chemotype. These chemotypes differ in the composition and concentrations of key alkaloids. The objective of this study was to evaluate the acute toxicity of the less toxic chemotype when administered in multiple doses to cattle. The results from this study suggest that cattle could consume enough of the less toxic chemotype of tall larkspur to be poisoned in a range setting.