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Coccidiosis is a Frequently Diagnosed & Often Misunderstood

coccidiosis in lambs

Coccidiosis in Lambs and Calves

Coccidiosis is a frequently diagnosed, but often misunderstood, cause of scoring and poor growth rates in calves and lambs. Most cattle and sheep are infected with coccidia but in the majority of animals the parasites coexist causing little or no damage. Actually, low levels of challenge are desirable as this will stimulate a protective immune response.

Disease only tends to occur if animals are subjected to heavy infection pressure or if their resistance is lowered by stress, intercurrent disease or poor nutrition. Coccidiosis in ruminants causes intestinal damage, resulting in depressed growth and performance and greater susceptibility to other infections. Coccidiosis is caused when cells in the lining of the animal’s large intestine become infected with protozoa parasite called Eimeria. The parasite multiplies in the intestinal wall and this rapidly destroys the lining of the gut.

In cattle and sheep, some species of coccidia are more pathogenic than others. In sheep, Eimeria ovinoidalis is the most pathogenic species while, in cattle, Eimeria bovis and Eimeria Zuernii are considered the main pathogens.

Clinical signs of coccidiosis in lambs and calves

In the UK, coccidosis is most commonly seen in unweaned lambs aged four to eight weeks on lowland farms where stocking rates are high, and usually affects twin and triplet lambs. Bovine coccidiosis is primarily a disease of young animals, normally occurring in calves between three weeks and six months of age after mixing groups of calves, although it also has been reported in cattle aged one year or more. Main signs of coccidiosis are:


  • Dark scour (with or without mucus or blood)
  • Inappetence
  • Abdominal pain
  • Anaemia
  • Sub optimal weight gain
  • Dry rough coat

Sub-clinical coccidiosis is often an “invisible” disease that can have a serious impact on calf and lamb production. This will present as suboptimal growth and may not be noticed unless you are measuring performance.

Some calves that survive clinical coccidiosis may never fully recover. They will have permanent gut damage and will never match the performance of their peers.

Always seek veterinary advice to confirm diagnosis so you get the right treatment, control and advice. Do not forget that there are a number of other conditions in older calves and lambs which can be confused with coccidiosis like Salmonella, Nematodirus infections at pasture or nutrition related conditions like mineral/vitamin deficiencies or poor general nutrition.
Diagnosis of coccidiosis in ruminants is based on the history, clinical and pathological signs, faecal oocyst counts and the species of coccidia present.

Treatment, control and prevention

Only a few licensed products such as Vecoxan are available for the treatment of coccidiosis; these can be administered either by injection, oral drench or as in-feed medication. It is of paramount importance to work with your vet as part of a team approach to figure out the best and most cost-effective treatment, as well as the optimum time for treatment, in order to reduce infection pressure on your farm. As a part of a comprehensive and cost-effective coccidiosis control plan any factors causing stress or poor hygiene should be effectively addressed:


  • Attention to hygiene
  • Mixed ages
  • Avoidance of overcrowding
  • Poor ventilation
  • Soiled bedding with warm environment

In order to avoid serious economic impact on calf or lamb production at your farm, it is of paramount importance to spot infection early and to seek veterinary advice to diagnose, treat, control and prevent coccidiosis by adopting a holistic approach to lamb/calves health management. At Molecare Veterinary Services we strive to find the most suitable treatment as part of a practical and cost-effective youngstock disease control plan.

Speak to an SQP (suitably qualified person) at your nearest store


Source Details

Candido Rodriguez-Cruz, BVet Med (Mad), MRCVS, Molecare Farm Vets

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