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Coccidiosis in cattle

Coccidiosis causes calf scours, poor gains, and 'nervous' cases. Learn the signs, amprolium and toltrazuril dosing, prevention, and vet guidance.

Bovine coccidiosis is caused mainly by Eimeria bovis and E. zuernii. It is specific to cattle.

Who is at risk

Calves around weaning and after stress (transport, weather, mixing) are most affected. A rare 'nervous' form can cause tremors and seizures in winter.

Symptoms of coccidiosis in cattle

  • Diarrhea, often bloody. Dark, bloody scours are a hallmark of heavier infections.
  • Straining (tenesmus). Calves strain persistently, sometimes prolapsing.
  • Reduced gains & dehydration. Even subclinical cases quietly cut weight gain.
  • Nervous signs (uncommon). A small subset develop tremors or seizures with a poor outlook.

When to act

Blood in the stool, ongoing diarrhea, dehydration, or a young cattle going downhill all warrant prompt veterinary attention. Confirm the diagnosis with a fecal test rather than guessing.

Treatment

Effective options for cattle include:

  • Amprolium. FDA-approved for cattle: about 10 mg/kg/day for 5 days to treat, or 5 mg/kg/day for 21 days to prevent. Follow with thiamine.
  • Toltrazuril. A single-dose triazine option used to prevent and reduce shedding in calves.
  • Sulfadimethoxine. A labeled sulfa option: a loading dose then a lower daily dose.

Pair any treatment with supportive care — fluids, nutrition, and a clean, dry environment. The dosage reference shows typical published figures; a veterinarian must confirm what's right for your animal.

Talk to a vet about cattle

Coccidiosis should be confirmed with a fecal test, and several anti-coccidial drugs require a veterinarian's prescription. Vetr connects you with licensed veterinarians who can diagnose, advise, and prescribe when appropriate.

Talk to a licensed vet

Prevention

  • Keep calving and weaning areas clean and dry, and avoid manure buildup.
  • Provide clean, uncontaminated feed and water off the ground.
  • Minimize stress at weaning, transport, and mixing.
  • Consider a coccidiostat in feed or a preventive amprolium program during high-risk periods; give thiamine after amprolium.

Is it a risk to me or other animals?

Cattle coccidia are host-specific and are not a risk to people or other species.

Frequently asked questions

What is the amprolium dose for calves?
The labeled 5-day treatment is about 10 mg/kg body weight per day; the 21-day prevention rate is about 5 mg/kg per day. Because amprolium interferes with thiamine, vitamin B1 supplementation is advised afterward. Always confirm the exact rate for your product with your vet — try the calculator on this site as a starting point.
What is 'nervous coccidiosis' in cattle?
A minority of severely affected calves, often in cold weather, develop neurological signs such as tremors and seizures. The outlook is guarded, so early treatment of the herd and veterinary care are important.
Should I treat the whole group?
Often yes. When one calf shows coccidiosis, the rest have usually been exposed, so many labels advise treating on a herd basis. Your vet can confirm the right approach.
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Questions about cattle coccidiosis?

A licensed veterinarian can confirm the diagnosis and advise on the right approach for your cattle. Vetr offers veterinary consultations.

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Educational information only — not veterinary advice, and not an offer to sell any product. Coccidiosis.com provides general educational information about animal health and does not diagnose, treat, or prescribe. Some medications discussed (including toltrazuril and diclazuril) are not approved by the U.S. FDA for use in animals, and others are approved only for specific species; any use must be determined and supervised by a licensed veterinarian, who can also advise on correct dosing and withdrawal times. Always consult your veterinarian before using any medication.