Horses occasionally get lice, and a horse owner needs to know what to look for and how to treat these irritating parasites. Bill Clymer, PhD, of Amarillo, Texas (now a livestock parasitologist on the professional services staff of Fort Dodge Animal Health), has worked with horses and lice for many years. Earlier in his career, he was an extension livestock specialist with Texas A&M University. We also talked to Jack Lloyd, PhD, professor of entomology at the University of Wyoming; and Sandy Gagnon, extension specialist at Montana State University, for this article