Chewing, blood-sucking lice are found on cattle throughout the world and the U.S. is no exception. Cattle infested with lice experience intense skin irritation, leading to scratching, hair loss, stress and lost gain. Allowed to persist severely, lice can cause anemia.

Lice are maintained through the warm months of the year in low numbers on carrier animals. As the hair on cattle increases and cattle bunch up in the fall and winter, populations of lice spread by contact and increase to a peak in February and March. An adult louse attaches its eggs to the hairs of its host where they hatch into nymphs. The lice life cycle is only about 28 days from egg to reproducing adult.

There are a number of insecticides available in spray, dip, pour-on and injectable forms to treat lice when they are discovered. However, entomologists suggest treating lice with insecticide in the fall to prevent severe infestations later in the winter and spring.