Lice can suck the profits out of your beef and dairy cattle herds during the winter. These cold-loving pests spread when animals bunch together in response to frigid temperatures.
You can reduce potential lice problems on newly bought cattle by keeping these animals separate from your herd until after you’ve given them a thorough louse treatment, generally two applications of a contact insecticide.
The first application kills active adults and immature lice but it won’t destroy nits or eggs on the hide. A second application targets new hatchlings from the nits and any other lice still around. Be sure to follow the label instructions on treatment intervals.
After these two treatments, you can add new animals to the herd with minimal chance of lice problems during the winter.
Don’t use systemic insecticides during the winter unless you know the treatment history of newly purchased cattle. This is because migrating grubs might be in sensitive locations and cause an adverse reaction this time of year.
Winter also is a good time to reduce future weevil problems in alfalfa by letting beef or dairy cattle graze dormant fields. Alfalfa weevils lay a significant number of their total eggs in living and dead stems.
Winter grazing helps manage alfalfa weevils in two ways. Grazing removes stems holding deposits of weevil eggs. And it removes stems that can serve as sites for females to lay the remaining eggs in the spring.
Letting your cattle graze alfalfa fields in the winter can reduce weevil populations substantially, possibly to the level that you won’t need a spring insecticide application.
For more information on controlling lice and other livestock insect pests, consult Extension publication ENT-11, AInsect Control on Beef Cattle — 2002 and EntFact 512, Lice on Beef and Dairy Cattle. Both publications are available from the Boyle County Cooperative Extension Service.
Jerry Little is Boyle County extension agent for agriculture/natural resources.