Toxic Plants in Grasslands and Their Impact on Livestock

Grasslands are critical infrastructure for most cow/calf operations. Quality and abundance of pasture grasses directly influence livestock rate of gain, thereby affecting livestock margins and production costs, which determine the profitability of stocker operations. Successful cattlemen control weeds to preserve healthy pasture but also to prevent plant poisonings that may reduce individual animal performance or cause fatalities. Integrated Toxic Plant Management (ITPM) programs teach ranchers to identify the potentially toxic plants, recognize symptoms of plant poisonings, and use appropriate strategies to control those plants. Toxic plants can produce a range of effects in cattle and other grazing species. Nightshades (Solanum spp.) cause gastrointestinal irritation and neurological problems. Star thistles (Centaurea spp.) cause a very specific brain damage in horses, preventing them from chewing and swallowing properly. Coffee senna and its cousins (Senna occidentalis, et al.) cause profound skeletal muscle destruction in cattle (alert downers) and heart muscle damage in goats and chickens. Other plants cause birth defects in calves and lambs [e.g., skunk cabbage (Veratrum spp.), lupines (Lupinus spp.)]. Plants containing pyrrolizidine alkaloids (e.g., Amsinckia spp., Senecio spp.), cause delayed, progressive liver damage that can take as long as a year to kill animals that consume them. An unknown number of animals are lost annually to preventable plant intoxications