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United States Department of Agriculture

Agricultural Research Service

Title: CATASTROPHIC CATTLE LOSS TO LOW LARKSPUR (DELPHINIUM NUTTALLIANUM) IN IDAHO

Authors
item Pfister, James
item Gardner, Dale
item Stegelmeier, Bryan
item Hackett, Kimberly - BLM
item Secrist, Glen - IDAHO DEPT. AGRI.

Submitted to: Veterinary and Human Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 20, 2003
Publication Date: June 20, 2003
Citation: PFISTER, J.A., GARDNER, D.R., STEGELMEIER, B.L., HACKETT, K., SECRIST, G. CATASTROPHIC CATTLE LOSS TO LOW LARKSPUR (DELPHINIUM NUTTALLIANUM) IN IDAHO. VETERINARY AND HUMAN TOXICOLOGY. Vol. 45, No. 3, pp. 137-139, 2003.

Interpretive Summary: Low larkspurs (Delphinium nuttallianum or D. andersonii) are common toxic plants on western rangelands. Cattle are often poisoned by low larkspurs during spring and summer. Even so, low larkspurs are usually not sufficiently toxic and abundant to kill large numbers of cattle at one time. Low larkspur populations may become more abundant during cold, wet spring weather, thus increasing the risk of losses. This report details losses of 53 animals in one poisoning episode near Shoshone, Idaho in May, 2002. Several factors were involved in inducing such a loss. First, climatic conditions in the local areas were ideal for low larkspur growth as the previous months of December, January, and March were wetter and much cooler than normal. Low larkspur populations were probably much more abundant than during normal years. Second, conditions for growing grass (particularly cheatgrass, the dominant spring forage for cattle) were poor. In mid-May, cheatgrass was very short and dry. Third, the toxic alkaloid concentration of the low larkspur was very high at 8.3 mg/g. Finally, a large number of cattle (> 20 animals) died while being moved out of the rugged pasture by ranch hands on horseback. The larkspur alkaloids effectively fatigue and paralyze the muscles of the legs and diaphragm, and the exertion of moving the animals also contributed to the death loss. Livestock owners and managers need to recognize toxic plants growing in their area. If there is an unusual abundance of larkspur or other toxic plants, then correct identification can provoke caution in grazing management. In this case, grazing should have been delayed until larkspurs dried out later in the spring.

Technical Abstract: Low larkspur (Delphinium nuttallianum) is a low-growing shallow-rooted perennial plant often implicated in livestock deaths during spring or summer. Low larkspurs generally grow on foothill or mountain ranges, and often initiate growth before other forage species. Availability of low larkspurs is often cyclic, as plant density and seasonal longevity are influenced by precipitation patterns and temperature. The toxins in low larkspur are diterpenoid alkaloids. Death losses to low larkspur are usually sporadic with only a few animals poisoned in each episode. This report details losses of 53 animals in one poisoning episode near Shoshone, Idaho in May, 2002. Several factors were involved in inducing such a loss. First, climatic conditions in the local areas were ideal for low larkspur growth as the previous months of December, January, and March were wetter and much cooler than normal. Second, conditions for growing grass (particularly cheatgrass, the dominant spring forage for cattle) were poor. In mid-May, cheatgrass was very short and dessicated. Third, the toxic alkaloid concentration of the low larkspur was very high at 8.3 mg/g. Finally, a large number of cattle (> 20 animals) died while being moved out of the rugged pasture by ranch hands on horseback. The larkspur alkaloids effectively fatigue and paralyze the muscles of the legs and diaphragm, and the exertion of moving the animals also contributed to the death loss.

Last Modified: 9/1/2014
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