Be coccidiosis aware with calves this autumn

Farmers with autumn calving herds are being encouraged to be vigilant for coccidiosis during the high-risk period, of three to four weeks post weaning, especially if the weather is mild and damp.

Phoebe McCarter, NADIS veterinary advisor, explains that coccidiosis remains a major issue across the industry and outlines how a combination of good husbandry, testing and prompt treatment with an appropriate coccidiocide can help gain control of the costly disease.

Prevention with good husbandry

“Many herds are still calved outside during the autumn, so one of the first things to consider is whether your field is likely to harbour disease risk, as coccidiosis oocysts can survive year-to-year from previous stock,” she says.

“I’d also recommend fencing off any stagnant water or natural watercourses, as these can harbour higher levels of the parasite. Similarly, poached areas around troughs and feeders make for oocyst survival conditions, so frequent relocation of these is key.”

Indoor calving herds have different risks to monitor for, so it is vital to ensure bedding is kept clean and dry, with sheds are cleaned down and disinfected appropriately.

Identify the species

Phoebe explains that on top of environmental pressures, periods of stress, such as weaning, castration or housing will leave calves more vulnerable to infection.

Therefore, at the first signs of disease, including weight loss, reduced appetite or a general dull appearance, it is essential to consult your vet to carry out diagnostic tests and oocyst counts, which will confirm the species and severity of the infection.

“There’s no point in treating calves for coccidiosis if it turns out to be a different disease with similar symptoms, such as cryptosporidiosis. You’ll end up wasting money on ineffective treatments and losing valuable recovery time,” says Phoebe.

Prompt treatment

Once coccidiosis has been diagnosed, the infected calves should be promptly treated, before clinical symptoms can develop further. Administering a toltrazuril based product, such as Baycox®, will stop the disease taking hold before it becomes more serious.

“This metaphylactic approach to treatment will help calves recover quickly and avoid major impacts on production, all while developing the calf’s immunity.

“As always, if you’re in any doubt about coccidiosis, speak to your vet about prevention and treatment, as the disease can rapidly eat into farm profits,” concludes Phoebe.

For further information on coccidiosis please visit and to find out more about Baycox, please contact your local Bayer territory manager.


Keep watch for the early subclinical signs of coccidiosis to be ready for immediate treatment

Signs of coccidiosis



Weight loss

Scouring (sometimes containing flecks blood or mucus)

Stunted growth

Dull and lifeless

Appearance of a ‘poor doer’

Painful vocalisation




Lack of appetite


Issued by: Hannah Wilson, Pinstone E: T: 01568 617661