Calf Note #17 – A Review of Coccidiosis in Calves

Coccidiosis, caused by protozoa of the genus Eimeria, results in health and economic problems to several classes of livestock. The disease reduces feed consumption, body weight, and feed efficiency and may cause mortality of 24% in some cases (Fitzgerald, 1975). An estimated 77 million young cattle in the United States could be infected by coccidia during the first year of their life. Of these, 4 million will be treated for coccidiosis, and 80,000 cattle could die from the disease (Fitzgerald, 1975). Annual economic losses due to coccidiosis have been estimated at $62 million (Williams, 1984). Coccidiosis commonly affects young cattle up to 2 years of age. Animals housed in proximity are more likely to contract the disease. Therefore, feedlot and dairy cattle are most susceptible. Coccidiosis in feedlot cattle is associated with stress caused by shipping, changes in ration and in weather, and overcrowding (Ernst and Benz, 1986). Stress caused by weaning makes dairy calves very susceptible to coccidiosis.