For ranchers, lice in cattle becomes growing problem

DICKINSON, N.D. - Cattle lice, a cold season insect, have been causing problems for cattle and ranchers this year after surviving treatments that usually eliminate them.

Erika Schumacher, a veterinarian at West Dakota Veterinary Clinic, said one reason cattle lice have been surviving through treatments could be because of the resistance they have built up to the chemicals.

“Sometimes we have to switch up and use a different product,” she said. “Bugs have nothing better to do than to reproduce, and they can kind of outsmart our drugs faster than we can make them and get them licensed.”

She said if stockmen come in with a lice problem after they have already treated their cattle, they switch up drug classes or will look at different products or brands, which usually alleviates the problem.

Gerald Stokka, a veterinarian at the NDSU Extension, said in a press release that lice have become more difficult to control now than they were 10 years ago.

“With the development of the ‘pour on’ products, along with the generic products, the use increased, and in some cases, these products were used multiple times per year,” he said. “So whether we are dealing with resistance in lice or less efficacy at the appropriate dose, the result is the same - a lack of control.”

While lice are mostly a nuisance to cattle, it can also affect their health if it is a large infestation due to the loss of blood, Schumacher said.

Schumacher said some cows will scratch large sores on their bodies by rubbing on posts or barbed wire.

She said it is important to stay ahead of a large infestation and looking for the signs before it becomes a major problem.

“If you start seeing red sores on your cows, you should definitely get them taken care of,” she said. “Look at the herd, and if you start seeing hair loss or they are rubbing a lot and you’ve already used something, talk to your veterinarian.”

John Kessel, an angus cattle rancher in Medora, said that this has been a strong year for lice, but winter ticks on horses have not been bad this year in comparison.

“You take the good with the bad,” he said.
Kessel said everybody he has talked to has had some issue with lice on their cattle this year.

“Some animals are affected more than others,” he said. “There are some cows out there that have got some hair issues and others look great.”

Kessel said he believes once the weather starts warming up most of the lice will die off, so he is not planning on re-treating his herd.

NDSU Extension recommends a few options to help curb lice outbreaks:

• Leave the cattle alone. In many cases, the best solution may be to just leave the cattle untreated. Lice populations will begin to decrease in activity rapidly as the weather warms.
• Work with your veterinarian to determine the type of lice you are treating. The likely culprits are the biting lice. Biting lice feed on the dander and scruff on the cattle’s skin and are controlled more effectively with a topical treatment. In contrast, sucking lice feed on blood and serum from the animal and are controlled more effectively with an injectable product that gets into the blood.
• Use injectable and topical treatment to control both types of lice.