Animal Health & Disease Management



Other common names: Black scours
Description: Parasite infection

Coccidiosis is a disease affecting not only in calves and young weaners but also older animals. The disease is caused by a group of intestinal protozoan parasites known as coccidia, which are only visible under a microscope.

Coccidia live in the lining of the guts of healthy adult animals who excrete them in their faeces. Coccidia can survive in the environment for long time and even survive disinfection. They are therefore picked up by young animals not only from pasture but also from dirty stable floors. Coccidia burrow in the wall of the lower gut, thus causing the disease. Incubation takes about 3 weeks from the time of infection. Weaned calves and young stock between the ages of 2 months and 2 years are all susceptible to the infection.


Signs of Coccidiosis

  • The affected calves pass out very soft faeces, usually of dark colour (“black scours”) because the faeces contain varying amounts of blood. One characteristic clinical sign of coccidiosis in calves is straining to pass out blood stained or very dark faeces.
  • The affected weaners, but also older steers and heifers up to 2 years, appear dull, weak and lose weight rapidly
  • They display discomfort and grind their teeth



Because some intestinal worms can cause similar symptoms the faeces from the infected animals should be taken to a veterinary laboratory for microscopic examination.


Prevention and Control

  • Ploughing and reseeding of infected grazing pastures can help to reduce the contamination with coccidia in permanent paddocks where the disease is prevalent
  • Careful rotation of calves in the grazing paddocks helps to minimize infection
  • Avoid confining calves to one grazing area for a prolonged period
  • Rest grazing paddocks for an ample time to avoid accumulation of pathogens
  • If stables are infected, clean out thoroughly with hot water and detergent to remove the coccidia


Recommended treatment

Only a few specific drugs have an effect on coccidia, they are called Coccidiostatics.  Administration of  coccidiostatic drugs, such as sulphonamides, nitrofurazone and amprolium by mouth controls the infection. Coccidiostatic drugs are more poisonous than many other drugs and  must be carefully dosed.

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