Coccidiosis poses a major risk for calves: How do you avoid it?

Coccidiosis has been on the increase in recent years. This is often due to a late spring, with the resultant late turnout of stock leading to a build-up of infection in calf bedding and creep areas.

It’s all about hygiene and cleanliness as the calving season progresses.

What causes coccidiosis?

As with cryptosporidia, coccidiosis is caused by protozoa.

Cattle will develop immunity to the condition over time, but young calves with an underdeveloped immune system placed in a dirty environment can succumb to the disease.

A dirty environment leaves calves more likely to ingest high numbers of the immature protozoa. Coccidiosis tends to be seen in calves from about three weeks old up to about six months.

Infected calves pass out large numbers of oocytes (eggs), which can contaminate the environment for other calves.

The oocytes are resistant and can survive for long periods in the environment.

Clinical signs

Coccidia can cause a watery scour because they damage the mucosa of the intestine.

Damage to the intestine reduces a calf’s ability to absorb fluids and nutrients. Calves that are infected can become dehydrated, may start to pass blood, shed part of the intestine lining and can become weak and uncoordinated.

Calves that have the condition can often be seen straining. Probably the biggest economic loss is the poor thrive in animals that are affected.

In many herds there may be sub-clinical infection where animals show very little symptoms and will recover with time, but thrive will be affected.


If a herd has had trouble with coccidia in the past then they need to be vigilant, because it can easily reoccur – particularly where hygiene is poor.

In this case, calves will often be dosed with Vecoxan or Baycox as a prophylactic. Typically calves will be given an oral dose of 20-30ml, depending on the weight of the calf.

Calves that are scouring become dehydrated and should receive normal electrolyte therapy. They should also be removed from the group.


Prevention is better than cure. Here, hygiene is hugely important. Increase the amount of straw bedding used in calf areas.

Try and prevent the build-up of faecal contamination around feed and water troughs. Avoid mixing of different ages of calves, as younger calves will be more susceptible.

Two friesian calves

If you have had a problem make sure sheds are cleaned and disinfected with a strong disinfectant (as recommended by your vet) between batches of calves. Disinfectant choice is critical; ensure that you choose one that kills oocytes.

Consult your vet on the most effective disinfectant to use.

The use of hydrated lime as an additional disinfectant is recommended. Animals can be given licensed medication, as already mentioned, to prevent the disease.

In some areas medicated licks containing coccidistats are used under prescription. It should be borne in mind that there is no vaccine available against coccidia.

Veterinary assistance

If you suspect that there is an outbreak of coccidiosis infection in your calves, prompt action is vital.

Consult with your vet immediately on your suspicions.

It is also important that, in a scour outbreak, a scour sample is taken to your local vet and sent to a veterinary laboratory to identify the causal organism and confirm that it is, in fact, coccidiosis.

Treatment of your calves will be very much dependent on the outcome of the sample results.

By Anthony O’Connor, Teagasc Adviser, Galway/Clare Regional Unit


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