Coccidiosis is an intestinal disease that affects several different animal species. The causative agent is a protozoan that has the ability to multiply rapidly. Coccidiosis is seen most commonly in calves that are six to twelve months of age. Calves become infected when placed on pastures contaminated by older cattle or by other infected calves. Coccidiosis in cattle is one of the five most economically devastating diseases of the cattle industry, and is projected to cost the industry $100 million annually.

Common Names

Coccidiosis is also known as Bovine Coccidiosis. Coccidiosis is primarily a disease of young animals but can affect older animals that are in poor condition. Nervous Coccidiosis is a nervous system condition associated with this infection.

Causative Organism

Coccidiosis is a virus caused by bovine coccidian. The organism has stages both within the host animal as well as outside it. In the developmental stages in the animal, the virus gives rise to a microscopic egg called an oocyst. This is passed onto the manure. Eimeria zuernii and Eimeria bovis are associated with the disease.

Common Symptoms

  1. Diarrhea
  2. Rough coat
  3. Loss of appetite and weight
  4. Weakness may cause the calf to defecate without rising
  5. Manure may contain blood and mucus
  6. Pneumonia
  7. Death may occur during the acute period

How it Affects Cattle

Coccidiosis occurs in all breeds of cattle. Calves acquire infection as soon as they begin grazing or eating food other than their mother's milk. Although the disease is seen more normally in calves six to nine months of age, it may occur in yearlings and adults. Cattle experiencing severe bouts of Coccidiosis may never perform as well as non-infected pen-mates. Infection also heavily affects the calf’s immune system and makes it more vulnerable to other diseases.

Regional Impacts

Most cases of Coccidiosis occur during the winter months but it may develop any time cattle are crowded together. Coccidiosis can also occur sporadically throughout the year in various regions of the location.

Risks & Dangers

Coccidiosis is frequently called as an opportunistic infection which develops when the cattle is affected by other conditions. The ingestion of oocyst may not produce the disease but some animals constantly carry them without being affected.


Treatment of infected animals is necessary. Individual treatment should be used when possible; but herd applications are more practical. Sulfa antibiotics are useful for secondary bacterial infections. Therapeutic doses of amprolium are also quite effective in treating the disease. Proper herd management can reduce exposure to disease by reducing stress.

Vaccines & Prevention

Good management practices are vital when establishing parasite control programs. The primary concern in Coccidiosis outbreaks is the possibility of spreading the disease to other susceptible animals in the herd. Drinking water and feed should be protected from contamination with manure. Infected animals should be isolated to avoid exposure to other cattle. Heavily parasitized animals should be secluded from the rest of the herd and then treated.

References and Resources