Horsetail is also called scouring rush and generally occurs along the edges of streams and in marshy areas. Poisoning results in loss of vigor, trembling, and eventually paralysis. Chokecherry is a common shrub or tree found throughout the state where moisture is plentiful. The leaves of chokecherry can produce hydrocyanic acid and cause abnormal breathing, trembling, convulsions, and death. Unexplained livestock illness or death is not always due to poisonous weeds.
Crops can also produce toxins under certain conditions.
Sudangrass and green flax straw may produce hydrocyanic acid after clipping or a light frost. In addition, livestock can become ill due to a nutrient imbalance, such as nitrate or selenium poisoning. Toxic nitrate levels commonly occur in many plants when growing under stressed conditions such as extreme drought. Lightning, venomous bites, or consumption of other toxic substances are other possible reasons for unexpected livestock deaths. However, recognition of common poisoning symptoms and identification of poisonous weeds is important to determine the possible cause of livestock illness or death.