Larkspur (Delphinium spp.) poisoning in livestock.

摘要: Larkspurs (Delphinium spp.) are toxic plants that contain numerous diterpenoid alkaloids which occur as one of two structural types: (1) lycotonine, and (2) 7,8-methylenedioxylycoctonine (MDL-type). Among the lycoctonine type three N-(methylsuccinimido) anthranoyllycoctonine (MSAL-type) appear to be most toxic: methyllycaconitine (MLA), 14-deacetylnudicauline (DAN), nudicauline. An ester function at C-18 is an important requirement for toxicity. Intoxication results from neuromuscular paralysis, nicotinic acetylcholine receptors in muscle brain blocked by alkaloids. Clinical signs include labored breathing, rapid irregular heartbeat, muscular weakness, collapse. Toxic alkaloid concentration generally declines tall larkspurs with maturation, but varies over years plant plant, little use predicting consumption cattle. Knowledge valuable management purposes when cattle begin eat larkspur. Cattle consuming larkspur after flowering racemes elongated, increases matures. Weather also a major factor consumption, tend more during or just summer storms. Management options may useful livestock producers conditioning avoid (food aversion learning), grazing ranges before (early grazing) seed shatter (late grazing), sheep cattle, herbicidal control plants, drug therapy intoxicated animals. Some potentially fruitful research avenues examining chemistry low plains larkspurs, developing immunologic methods analyzing alkaloids, therapy, devising regimes specifically