Catastrophic cattle loss to low larkspur (Delphinium nuttallianum) in Idaho.

Low larkspur (Delphinium nuttallianum) is a toxic plant found on many western US rangelands. Episodes of fatal poisoning are often related to the abundance and toxicity of the low larkspurs. This report documents the fatal intoxication of 53 cattle in a herd of 404 animals in south-central Idaho during Spring 2002. Low larkspur had a toxic alkaloid concentration of 8.26 mg/g. Several factors were involved in a loss of this magnitude, including climatic conditions ideal for low larkspur growth, poor grass growth during the spring, the high alkaloid concentration in larkspur, and the deaths of many cattle while being moved from the pasture. It is important for livestock owners and managers to recognize toxic plants growing in their area. If there is an unusual abundance of larkspur or other toxic plants, correct identification can provoke caution in grazing management.