16 February 2012

2 minute read

North America

Cold weather in mid- to late winter in Indiana means cattle are spending more time in close proximity to each other. Any time producers bring cattle together there's an increased risk for lice to spread, said Ron Lemenager.

"Lice populations are fairly low in the summer, but they tend to peak this time of year," he said. "Producers need to watch for obvious signs, such as rubbing or scratching on objects, patches of hair falling out, reddening of the skin or even serum oozing from the hide."

Cattle can take on a greasy appearance at a high level of infestation, Mr Lemenager said.

The areas of the animal most commonly affected are the brisket, dewlap, head, neck, shoulders, top line and tail head. Producers need to keep an eye on these areas of their animals for the presence of lice or white, oblong eggs, also known as nits.

Indiana has four main species of lice - three sucking species and one biting. All four can be treated with one type of insecticide, said Ralph Williams, Purdue Extension entomologist.

"Pour-on treatments containing pyrethroids will take care of both sucking and biting lice," he said. "But, it's important to remember only to treat if necessary."

Producers who find it necessary to treat their animals need to keep in mind that the entire herd will require treatment - not just those animals with symptoms.

"An animal that is a carrier may have a low population and not show symptoms, but when cattle are brought together during the winter, the lice spread," Mr Lemenager said. "If you only treat those animals with symptoms, you might still have carriers that can recontaminate the herd."

Before treating, he said producers need to read the insecticide labels and if they have questions regarding proper treatment, consult with herd health providers.