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Tuesday 24 October 2017

Farmer loses four calves as killer parasite levels on farms hit 24pc

Vet labs diagnose Coccidiosis in 24pc of weanlings

Coccidiosis has been on the increase in recent years, due mainly to the late spring, with the resultant late turnout of stock leading to a build-up of infection in calf bedding and creep area. Stock image
Coccidiosis has been on the increase in recent years, due mainly to the late spring, with the resultant late turnout of stock leading to a build-up of infection in calf bedding and creep area. Stock image
Ciaran Moran

Ciaran Moran

A farmer in Cork lost four weanlings to coccidiosis this summer as the condition was found to be rampant in cattle examined at regional veterinary labs (RVL) around the country.

During the summer, coccidiosis was diagnosed in 24pc of submissions from bovine weanlings across all RVLs.

In an example of an unusually severe presentation of the disease, a heavy parasitic load of coccidia and nematodes was observed in a group of eight seven-month-old weanlings by Cork RVL.

The clinical signs were weakness and diarrhoea, progressing to recumbency. Four calves died in total.

Breakdown of pathogens identified in cases of bovine enteritis from all age calves in May and June 2017. Source: Department of Agriculture
Breakdown of pathogens identified in cases of bovine enteritis from all age calves in May and June 2017. Source: Department of Agriculture

Botulism was considered as a tentative differential diagnosis by the veterinary practitioner at the early stages of the clinical examination and investigation, as weakness was the main clinical sign observed and so many animals were affected over such a short timeframe.

However, following consultation with laboratory staff, it was agreed that since there was no history of exposure to poultry litter and a typical flaccid paralysis was not observed, this differential diagnosis was less likely.

Examination of the intestinal sections taken at necropsy revealed marked infiltration of eosinophils and abundant coccidial oocysts at various stages of their life cycles, from merozoites to microgamonts and macrogamonts.

The severity of the intestinal lesions was considered adequate to confirm severe acute coccidiosis as the cause of death.

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Teagasc Adviser, Anthony O'Connor recently highlighted that coccidiosis has been on the increase in recent years, due mainly to the late spring, with the resultant late turnout of stock leading to a build-up of infection in calf bedding and creep area.

He says it’s all about hygiene and cleanliness as the calving season progresses.

What is 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 3 weeks old up to about 6 months.

Infected calves pass out large numbers of Oocytes which can contaminate the environment for other calves. The Oocytes are resistant and can survive for long periods in the environment (sheds etc)

Clinical Signs

The Coccidia can cause a watery scour because they damage the mucosa of the intestine. Damage to the intestine reduces the calf's ability to absorb fluids and nutrients and so calves that are infected can become dehydrates, 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.

Treatment

According to Teagasc 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 herds will often dose calves with Vecoxan (diclurazil) or Baycox (toltrazuril) as a prophylactic.

Typically calves will be given an oral dose of between 20-30ml depending on the weight of the calf.

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

Prevention

Prevention is better than cure.

Here, Teagasc says hygiene is hugely important.

Increase the amount of straw bedding used in the calve 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.

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 that kills oocytes is critical.

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 licenced medication as already mentioned to prevent the disease.

In some areas medicated licks containing Coccidistats are used under prescription. Please note 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 veterinary surgeon immediately on your suspicions. It is also important that in a scour outbreak that 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 Coccidiosis.

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


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