Anthropogenic lead is the most common cause of poisoning in ruminants. Vehicular lead emissions pollute herbage by the road, which may pose a risk to grazing ruminants. A series of experiments was conducted first to determine whether livestock could detect lead in herbage, and if so at what levels, and second whether they avoided lead contaminated herbage. The effects on grazing behaviour were recorded to investigate whether cattle could alter their grazing strategy to reduce their intake of lead from contaminated pasture.