Alkaloid levels of a tall larkspur species in southwestern Alberta

Tall larkspurs (Delphinium spp,) are widely distributed in western North Am erica and they kill more cattle on rangelands than any other poisonous plan t. In Alberta, Canada, D, brownii Rydb, has a long history of causing cattl e poisoning. The neuro toxic norditerpenoid alkaloid methyllycaconitine (ML A) was first detected in D, brownii over 50 years ago. A 2-year (1996 to 19 97) survey was conducted on the levels of MLA in D, brownii collected at 5 sites in the foothills of southwestern Alberta, The vegetative stage of gro wth yielded the highest levels of MLA and the decline and change in concent ration during that interval could be predicted on the basis of Julian day a lone, The MLA levels during bud to pod development mere not significantly d ifferent but they exceeded the reported levels for MLA in low larkspur by 5 - to 10-fold, A new method is described for the determination of MLA by HPL C.