Attempts to produce experimental Eimeria wyomingensis infections in calves

Attempts were made to produce repeatable infections with Eimeria wyomingensis in 2- to 4-wk-old calves. From 0.2 million to 10 million sporulated oocysts, or sporocysts from 1 million sporulated oocysts were given orally to 50 calves. Several regimens of flumethasone and dexamethasone at excessive dosage levels were given to some to the oocyst-inoculated calves. Nine of 10 calves given flumethasone and one of 12 calves given dexamethasone treatments died. Of the 41 calves which survived past post-inoculation day 21, 32 had patent infections. The prepatent period in the 32 infections was 13 to 15 (mean 14.2) days and the patent period was 1 to 7 (mean 3.6) days. More fecal oocysts were excreted by calves given sporulated oocysts than those given sporocysts. Calves given corticosteroids passed fewer oocysts than nontreated calves.