Coccidiosis in calves

Natascha Meunier, programme manager, Beef HealthCheck Programme

A common cause of scour in calves is coccidiosis, usually affecting them from three weeks to six months of age.

Coccidiosis is caused by a parasite that damages the cells in the intestinal lining, resulting in the clinical signs of scour, typically a bloody diarrhoea accompanied by straining, dehydration and a loss of condition. Affected animals often suffer from poor thrive affecting growth rates, even if they don’t show other symptoms.

Prevention and early action are important as calves can take a long time to recover.

Calves that are ill should be isolated away from the group in a warm, dry environment. Treat the scouring calf with replacement electrolyte fluids (one or two extra feeds of 2l each) as they easily become dehydrated. Continue to offer normal amounts of milk or milk replacer to calves that are drinking milk. Suckler calves should be left with their dams.

Parasite damage

By the time clinical signs are seen, most of the parasite damage to the intestine has already occurred. On farms with a history of coccidiosis, using strategic treatments at high-risk periods can prevent clinical disease. The active ingredients effective against coccidiosis are diclazuril and toltrazuril, available as an oral dose, and decoquinate as a premix on veterinary prescription. For any scour outbreak, it is important to get an early diagnosis.

Consult your veterinary practitioner for the most appropriate treatment and prevention measures. Medication should not be used in place of addressing poor hygiene practices and a dirty environment.

The oocysts (eggs) from the parasites survive very well in the environment and only specific disinfectants are effective. Speak to your veterinary practitioner about which product to use. The oocysts can remain infective for over a year and using the same pasture year on year for calves can increase the risk of coccidiosis. Contaminated surface water or areas around troughs can also be a source of infection.

Moving feed troughs at pasture can help avoid build-up of faecal contamination and fix leaking water troughs.

Feed and water troughs should be cleaned regularly, bedding for calves should be kept dry, with extra straw as needed, and shed should be disinfected after housing.

Cattle develop immunity to coccidiosis over time and clinical disease is not common in animals over six months old. Older animals can be a source of infection for younger calves, so avoid mixing calves from different age groups.

Control of Johne’s disease in Ireland

Lawrence Gavey, programme manager, Irish Johne’s Control Programme

The Irish Johne’s Control Programme (IJCP) enables Irish farmers to take control of Johne’s disease infection in their herds to improve animal health and productivity. For those herds that are not infected, farmers can use the programme to be confident of their status and protect against entry of infection into their herd.

The economic impact of Johne’s disease on a herd can be significant depending on the severity of the disease on-farm. The costs are estimated to range between €13.80 per cow to over €200 per cow per annum in the worst cases of infection. Costs are associated with reduction in milk production and increased costs in terms of animal health. Therefore, for herds with Johne’s disease, participation in the IJCP is important as it supports the farmer in tackling and managing infection and for those herds without the disease, it prevents entry of infection and the associated costs of having Johne’s disease in the herd.

There are three main activities that form the IJCP:

  • Annual veterinary risk and management plan or VRAMP.
  • Yearly herd test.
  • Veterinary investigation where a herd has been identified as positive, known as a ‘TASAH’ investigation.
  • The VRAMP comprises an on-farm risk assessment by a trained veterinary practitioner where three practical actions are agreed with the farmer to address infection on their farm. An annual herd test is conducted using either milk (taken at the time of milk recording) or blood samples from all cattle over two years of age.

    Additional or ancillary testing of dung may be required from animals with positive or inconclusive results to the milk or blood tests. Annual herd testing provides increasing assurance that a test-negative herd is not infected, or confirms infection and identifies infected or other high-risk animals. The TASAH investigation identifies the source, spread and impact of infection and to inform control measures the farmer can take.

    Funding is available to participating herds which either partly or fully offsets the costs of these programme activities.

    The industry-supported IJCP is a unique programme, which offers financial supports and provides the opportunity to farmers to either manage Johne’s infection or provide assurance to those that the infection is not present in their herd. The programme is suitable for both dairy and beef herds.

    For more information, contact AHI on 071-967 1928 or see our website,