Winter Lice In Cattle

It’s winter (despite our unseasonably warm weather right now!) and it’s time to consider another important but often overlooked part of cattle management. While we spend lots of time focusing on nutrition during this time, when there is little to no grass, and preparing for calving season, we should also take one other tiny pest into consideration: lice. Winter is the perfect time for lice infestations in both mature and young cattle. While lice can be present on cattle year round, their numbers greatly increase during the winter.

Types of Lice & How to Find Them

Both biting and sucking lice can be found on cattle, and can be detrimental to our herds. Lice spend their whole life cycle – egg, nymph, and adult – on the host, and normally all three stages are present at one time. Clinical signs suggesting a lice infestation include frequent scratching or rubbing on fences, posts, and other structures, and hair loss. Lice can be visualized on cattle by parting the hair and looking around the neck, brisket, tail head and between the rear legs. Lice on cattle can cause stress and decrease weight gain, so control is important.

Treatment

A systemic pour-on or injectable insecticide (an ivermectin product) is often the most common method for treatment of lice in cattle. Late October through January is often the recommended time for treating lice. All cattle in the herd should be treated at this time. Timing of treatment may be more important if your pour-on contains a grubicide. Typically medications containing a grubicide should not be administered between November 1 and January 1 due to the potential reaction of grub larvae in the spinal column to cause paralysis to cattle. Sometimes two treatments for lice may be needed throughout the winter months.

Help increase the comfort and health of your cattle in the cool months by treating for lice!

Call our Large Animal Veterinarians at 540-788-6094 with any questions about parasites or care for your livestock!