A common wintertime pest in cattle herds — lice — can suck money from producers’ pockets, said Dr. Jason Banta, Texas A&M AgriLife Extension Service beef cattle specialist in Overton, Texas.
Banta said lice can infest cattle throughout the year, but more problems are seen from December to March. “As the weather gets colder, cows grow longer, thicker hair and that produces better cover and protection for lice, which means the lice have better reproductive rates,” he said.
Banta said there are two types of lice that affect cattle herds: biting lice and sucking lice.
“Lice will cause reduced appetite in a herd, which means reduced performance,” he said. “It’s important to be aware of the pest this time of year.”
Lice can also reduce red blood cell counts by 75%, and animals with heavy infestations can become anemic, Banta said.
The pests are transmitted through physical contact between cows, he said. Breaking their life cycle is the key to lice control.
“It’s important to know that available treatment products don’t kill the eggs,” he said. “So, many control methods will take two treatments before the life cycle is broken. Always treat every animal in the herd, because that one you don’t treat will be the one that causes another infestation for you to deal with.”
Banta said if using traditional insecticides like Cylence or most permethrin-based products, then an initial insecticide application should be made to knock down lice populations, followed by another application two to three weeks later.
There are products available like Standguard and Clean-up II that require only one treatment. Additionally, certain pour-on dewormers — including Eprinex, Cydectin and Dectomax — only need to be applied once for season-long control, Banta said.
“If you go with an injectable dewormer for internal parasites, it’s important to know they only get the sucking lice and won’t control biting lice,” he said, adding that with injectable dewormers, "make sure (to) use a pour-on insecticide to take care of the biting lice.”
Always read and follow label directions when using dewormers and insecticides for control, Banta said.
Any new cows or bulls should be treated prior to introduction to the herd, he added.
“After the treatment regimen, your cattle will typically be in good shape until the next fall or winter,” he said. “Treat them, control them and you’re done.”