Frequently Asked Questions About Coccidiosis
Coccidiois is an animal health problem caused by certain micro-organisms called coccidia or oocysts. They are hidden from sight and can live for years in the environment, surviving under normal heat and cold changes. Stress caused by weaning makes dairy calves very susceptible to coccidiosis.
Coccidiosis is often called the "Silent Thief". Only about five percent of the calves show the clinical signs (bloody diarrhea); the other 95 percent have the same parasites that invade the small intestinal lining and impair nutrient absorption, and reduce growth rate and feed efficiency.
The typical life cycle for the Eimeria species of bovine coccidia lasts about three to four weeks. The sporulated oocysts are ingested by the calf and rupture, releasing sporozoites which infect epithelial cells of the intestinal mucosa. If the sporozoites are not stopped at this point of the life cycle, they continue to reproduce (asexually) within the cell wall, developing into millions of organisms. After about 14 days, the organisms reproduce sexually and invade the large intestine, causing hemorrhaging which results in the clinical signs of bloody diarrhea. Damage to the intestinal lining may become permanent, resulting in poorly performing animals. In severe cases, death occurs as a primary result of the diarrhea, which causes a loss of electrolytes and dehydration.
What is Coccidiosis ?
I donít see any evidence of coccidiosis, why should I be concerned ?
What is the Coccidia Life Cycle?
When do calves ingest the infective parasites (oocysts) ?
Calves ingest oocysts right from the start, by licking haircoats, nibbling on bedding and other contaminated materials.
Why donít I see any signs of coccidiosis until four weeks of age or older ?
The oocysts take 3 to 4 weeks to develop, cycle through the digestive tract and cause the diarrhea symptoms. The infection begins at the time of ingestion. Itís during the development time that the parasites do their damage. Prevention is the best method for control.