Lice: A Seasonal Lesson

Winter can mean lice infestations in livestock. Learn what to do if the pesky insects cause issues on your farm.

by Anna O'BrienDecember 9, 2019
PHOTO: C. Hamilton/Shutterstock

With winter’s chill now fully unleashed in many parts of the United States, you might find livestock on smaller farms inside their shelters, huddled closely together for protection against the elements. A nicely bedded pen sure can be cozy on a cold, winter day—both for animals and ectoparasites. Winter is the most common time for lice infestations in livestock, particularly cattle.

All About Lice

Most of us have heard of lice at some point—remember those compulsory head checks in elementary school? If the word itself isn’t enough to cause some involuntary itching, consider the mental image: a tiny, wingless, six-legged insect about the size of a sesame seed.

There are two general types of lice, and their names don’t make them any more endearing: sucking and biting/chewing. These monikers refer to how the pests feed: sucking lice pierce the skin of the animal and suck its blood, while biting/chewing lice have impressive mouth parts for munching on dead skin and hair. For most of the cattle in the U.S., there are four predominant species of the ectoparasites: one biting/chewing and three sucking species. It is common to have mixed infestations with multiple species.

Picky Eaters

Feeling a bit too itchy right about now? Take heart—lice are host-specific. This means that cattle lice typically only prefer cattle, and horse lice aren’t interested in non-horse hosts. So even if the beasts in your barn do come down with an infestation, you aren’t at risk of a co-infestation inside your home. (This is not the case with some other ectoparasites, such as ticks and mites.)

Cattle with lice are very itchy. They will scratch on almost anything, causing potential damage to fences, trees and sheds. They may have coats that appear worn with bald patches, especially on the shoulders, neck and rump; sometimes parts of the face will also be affected. Animals that are immuno-compromised, underweight or otherwise unhealthy—from respiratory disease or internal parasites, for example—typically have more severe infestations as compared to healthy animals.

Severe lice infestations can kill an animal, but this is rare and typically a result of multiple health issues. More commonly, infestations are an animal welfare issue due to the severe irritation they cause. Infestations can also impact production; heavily infested animals don’t gain as much weight, and damage to the hide may impact sale value.

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Winter Woes (and What to Do)

The louse life cycle is fairly short, about 20 to 30 days in length, and occurs directly on the animal for its entire length. Although lice are present all year long, numbers dramatically increase in the winter because the hair coat is longer and lice are protected. Additionally, lice are spread through animal-to-animal contact, so when animals pack together for warmth, lice populations explode. As weather turns warmer, sunshine, shorter-hair coats and fewer opportunities to hop from animal to animal result in a decline of the lice population.

Fortunately, if you notice a problem in your cattle, there are products on the market for treatment, including sprays, dusts, injectables and pour-ons. Most are highly effective against all common types of lice in the U.S. Timing of treatment is important, as some products require re-treatment for full effect. Always read the product label, and ask your veterinarian for treatment advice that is specific to your farm and your animals’ needs. Likewise, if you purchase new animals in the winter, keep them in quarantine until you’ve confirmed they are disease-free. If they are infested, treat prior to releasing them into your herd.

Livestock lice may be an itchy topic to read about, but learning how to combat infestations can save your animals a great deal of discomfort.