With the frigidity of winter comes the realities of needing to continue to manage external parasites of cattle. Regardless of an operation’s size or type, when it’s winter, we’re dealing with lice here in the West.

Small meranda
Idaho County Extension Educator / University of Idaho

Lice affect cattle by feeding on either blood or skin and are incredibly itchy. Affected cattle will rub and scratch on anything that provides relief, which results in patchy hair loss on the neck and rump and may eventually lead to facility damage. This in turn negatively impacts feed efficiency, milk production and growth.

Severe infestations can also result in anemia or low red blood cell count, skin infection and increased exposure to other diseases. Infestations often occur when cattle are experiencing cold stress and crowded together in sheltered areas. Lice infestations are further compounded by inadequate nutrition, internal parasite presence and weakened immune status.

The life cycle of lice is approximately three to four weeks, with the entirety of it spent on the host and spread through direct animal-to-animal contact. Lice management can be accomplished through multiple methods including backrubbers, dust bags, pour-on products and injectables. As is done with fly control, when implementing backrubbers and dust bags, they need to be placed in areas where cattle pass through on a daily basis in order to accomplish efficacy.

When choosing to use a pour-on product, it is important to accurately dose animals to ensure the product works as indicated on the label and to consider timing of product use. During weaning, products are available that target live lice but also kill eggs to reduce potential infestation. With the opportunity for cattle to be infested with multiple species of lice, it would be recommended to implement more than one method of control.


Consult your veterinarian for specific product and treatment regimen advice specific for your herd.