Farmers who have scouring calves that are passing blood should not assume it is Coccidiosis. It is important that farmers consult their veterinarians as soon as possible and that tests are done to confirm the problem, as it could be other causes.
Coccidiosis is found in calves that are overcrowded and kept in dirty areas where there has been a build-up of the protozoa, which causes the disease. The coccidia then multiplies greatly in the calves' intestines, adding to the problem.
The protozoa are always around, but dirty overcrowded conditions cause a rapid build-up and the disease takes its toll. They are very host-specific so the coccidia that causes problems in poultry are different from those that affect calves.
It's important that sheds used to rear calves are thoroughly cleaned out each year, and that the handy paddocks used for calf rearing are given a rest.
Try especially to avoid new groups of calves going on to areas recently contaminated by previous batches of calves.
It's also important not to use medication unless it is needed. It is better to rely on good husbandry rather than drugs if possible.
As well as in 4-6 week calves, coccidiosis can become a problem in the yearling stage. If yearlings are not thriving then it is worthwhile consulting your veterinarian to check out for parasites and coccidia.