– Mark Landefeld, OSU Extension Educator
Cattle Lice -Winter is the prime time for lice populations on beef cattle to increase. As temperatures cool and hair coats grow longer producers need to be monitoring their livestock. Constant rubbing is a sign or indicator your livestock may have biting and or sucking lice. Both biting and sucking lice are spread by direct contact with other animals and these parasites can cost producers a lot of money. Some loss comes from production loss, but other losses occur when livestock rub equipment, fences and buildings causing damage to them. A few cattle have lice year-around and are called carriers. This may only be 1-2 percent of the herd (usually older cows or bulls), but they can re-infect the other animals causing increased populations among all the livestock.
Biting lice survive by feeding on the skin, hair and sloughed skin cells of the animal. A complete life cycle of biting lice can occur in as little as three weeks, and adults can live as long as 10 weeks. The adult biting louse has a brownish-amber color head with a darkly outlined abdomen with a series of brown crossbars on a pale background. It is commonly found near the base of the tail and along the topline of the animals.
Sucking lice, on the other hand, are a more serious pest that survives by penetrating the skin and feeding on the host’s blood. Sucking lice are generally dark in color and typically found over the shoulders, down the animal’s neck, on the ears, dewlap or brisket. The shortnosed louse can complete its life cycle in about 28 days, although the time may range from 3–6 weeks.
Treatment in Ohio– The non-systemic insecticides are effective against all types of lice, whereas the avermectins, moxidectin and eprinomectin (systemic products) mainly kill sucking lice according to Lee Townsend, University of Kentucky Extension entomologist. Non systemic insecticides should be used from November 1st through early January if cattle were not previously treated for internal parasites (grubs). During this time there is a potential risk of choking, bloat, or paralysis from a response to cattle grubs dying in critical tissues within the animal if systemic insecticides are used.
Non-systemic insecticides come as pour-on products, dust bags, sprays and products for cattle rubs (like the pyrethroids cyfluthrin, lambda-cyhalothrin or permethrin) that can be used safely during the November to early January period. If non-systemic products are used, a second application is usually necessary in approximately 3 weeks to kill lice that were in the egg stage during the initial treatment. Read the label of the product being used to be sure of correct treatment procedures and note any withdrawal times that need followed.
Be sure to avoid parasite introductions onto the farm when purchasing new animals. Ask about previous history and management practices to reduce chances of unwanted parasites being brought in.