To begin with, there is no effective, safe chemical to apply to the soil to kill the coccidia cysts. Over time, the cysts die from the drying and rays of the sun. Preventive measures are focused on sanitation by reducing manure and providing clean, dry environment. Once a calf is infected, it becomes a lifetime carrier but has lifetime immunity to prevent recurrence of coccidiosis. A non-stressed calf with immunity does not get coccidiosis a second time. As for this show calf, it went through coccidiosis; the disease ran its course as immunity developed and suppressed the coccidia in the intestine. The calf remains infected with the suppressed coccidia and has immunity to prevent recurrence, there is no cause to be concerned for this calf. The problem of coccidiosis is always with new calves that haven’t been exposed and have no immunity. Sanitary measures will reduce the numbers of cysts ingested by new calves. Calves ingesting low numbers of cysts will have an infection without the full-blown disease but these calves will build immunity. All calves become infected; only those that ingest large numbers develop the disease.
Cattle fed recommended dosages of ionophores are known to have greatly reduced incidence of coccidiosis. Ionophores (monensin or lasalocid) are feed ingredients that have been used to improve feed efficiency in both feedlot cattle and pasture cattle that are receiving supplements. Many weaning or receiving diets include a feed ingredient (decoquinate) designed to prevent coccidiosis.