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As we move into the colder months, producers may need to start thinking about lice control in the cow herd.
Lice populations really ramp up during winter, with numbers typically peaking in January and February. Catching problems early can help prevent rubbing, hair loss, and reduced performance — and it’s one of the simpler winter management tasks to stay ahead of.
Nebraska Extension Entomologist Dave Boxler shares: If you suspect lice, take a few minutes to get a closer look.
The best way is to run animals through the chute and part the hair along the topline, withers, and face. When you part the hair, look closely for small, flat insects moving on the skin or attached near the base of the hair.
You may also spot tiny white or yellow eggs — called nits — stuck to the hair shaft. Both are signs lice are present and actively feeding.
A few lice — maybe one to five per square inch — is considered a low infestation. Six to ten is moderate. But once you’re seeing ten or more, that’s a heavy load, and treatment is usually warranted.
There are several treatment options available. Non-systemic pour-ons and sprays work well for winter control. Systemic products — including systemic pour-ons and injectables — can also kill lice, but they shouldn’t be used between November and February if a systemic product wasn’t already applied in the fall due to cattle grubs. Animals carrying cattle grubs can have adverse reactions to systemic products during this window while grubs are in the esophagus or spinal canal, so it’s important to keep in mind when making product choices. One other key reminder: rotate chemical classes. Using the same product year after year increases the risk of resistance.
Rotating modes of action helps keep treatments effective long term and protects the tools we have available.
Heavy lice loads aren’t just a cosmetic issue. UNL research shows that cattle carrying significant lice burdens can lose about twotenths of a pound of gain per day. Over the winter, that adds up — especially for growing calves or cows that need to maintain condition going into calving.
As we head into the colder stretch of the year, keep an eye out for cattle lice. Take a few minutes to check the herd, identify any problem animals, and choose a treatment strategy that fits your operation. A little attention now can prevent rubbing, hair loss, and lost performance later on.
For more information on this topic, and for a detailed list of insecticides along with their group number, visit beef.unl.edu.
-Ben Beckman is a beef systems Extension Educator northeast Nebraska. He is based out of the Cedar Connty Extension office in Hartington. You can reach him by phone: (402) 254-6821 or email: ben.beckman@ mailto:[email protected] unl.edu
