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Herd Health & Cattle CareExternal Parasites: Flies, Lice, and Ticks
Flies, lice, and ticks cost cattle comfort, gain, and health. Each one needs a slightly different plan, and a good program mixes management with careful use of approved products.
Key points
- Flies, lice, and ticks each need their own approach.
- Sanitation and breeding-site control reduce flies.
- Check cattle for lice in winter and ticks in tick season.
- Rotate and use products only as the label and your vet direct.
- Wear protective gear and store chemicals safely.
Why external parasites matter
Cattle bothered by pests eat less, move around more, and lose condition. Some of these pests also carry disease, and heavy infestations can cause anemia, skin damage, and hide problems. The effects add up in calf gains and cow condition.
Because each pest has a different life cycle and season, the best control depends on knowing which one you are dealing with.
Stress from pests also raises the risk of other problems, such as pinkeye from flies. Good control often helps you with more than one issue.
Flies
Several flies bother cattle, including horn flies on the back and shoulders, face flies around the eyes and nose, and stable flies on the legs. Each breeds in different places, from fresh manure to rotting feed and wet bedding.
Sanitation helps. Clean up spilled feed and old hay, manage manure where you can, and keep breeding sites dry. Our guide on fly control on beef ranches covers the options in more detail.
Mineral feeders, sprays, ear tags, and other tools are used in many programs. Which fits your ranch depends on your fly species, your cattle, and what the label allows, so ask your vet or extension specialist before you buy.
Lice
Lice spread by direct contact and are most active in cool weather. They cause itching, rubbing, hair loss, and a rough coat, and heavy cases can leave cattle thin. Calves and thin cattle are the most affected.
Look closely at the neck, shoulders, tailhead, and along the back in winter. Ask your vet to confirm what you are seeing, since mange and nutritional problems can look similar.
Lice populations tend to build through winter and peak in late winter. Plan to check cattle after cold stretches, especially thin ones and calves.
- Rubbing on posts and feeders
- Patchy hair loss
- Rough, dull coat
- Scratching and restlessness
- Thin cattle with no other cause
Ticks
Ticks feed on blood, and in some regions they carry diseases that cause serious illness. They are most often found on the ears, neck, belly, and inside the legs. Tick season and species depend on where you live.
Check cattle regularly in tick country, especially animals brought in from other areas. For tick-borne illness, see our guides on tick-borne diseases and anaplasmosis. Call your vet if you find heavy infestations or sick animals.
Building a control plan
A good plan combines steps: reduce breeding sites, watch cattle for early signs, keep animals in good condition, and use approved products as your vet and the label direct. Rotating product types helps slow resistance, but the specifics should come from your vet or extension specialist.
Do not mix or double up products on your own, since some combinations can harm cattle. Follow label directions and any withdrawal period exactly.
Check that any product you plan to use is labeled for your class of cattle, including lactating cows, young calves, and bulls. Labels differ and mistakes can harm animals.
Records and safety
Write down when pests appear, which group is affected, what you did, and what happened. These notes reveal the season when trouble starts and help time your response.
Wear the protective gear listed on product labels, store chemicals in a locked, labeled place away from feed, and keep children away. Follow OSHA and manufacturer guidance for chemical handling.
Common mistakes
Using the same product year after year, ignoring sanitation, treating at the wrong time of year, and missing lice until cattle are thin are common errors. Another is bringing in cattle without checking for ticks and lice. Ask your vet about checking and treating new arrivals before they join the herd.
Do not ignore the cattle that are rubbing and losing hair. Early treatment prevents thin cattle going into calving season.
Sources and further reading
Organization homepages are linked so you can search them for current guidance on this topic.