Evaluation of decoquinate, lasalocid, and monensin against experimentally induced sarcocystosis in calves.

Effects of decoquinate, lasalocid, and monensin against experimentally induced sarcocystosis (Sarcocystis bovicanis) were evaluated in 12 calves, 3 of which were inoculated, nontreated controls. Three additional calves were noninoculated, nontreated controls. Drugs were administered in the feed (33 mg/kg of feed) of the treated calves (3 calves/group) for 87 days. Eight of the 12 inoculated calves died from acute sarcocystosis during the experiment (the 3 inoculated, nontreated controls, the 3 calves given decoquinate, and 2 of the 3 calves given lasalocid). Large numbers of sarcocysts were found in tissues from inoculated calves that survived in the experiment (1 of the 3 calves given lasalocid and the 3 calves given monensin). Although large numbers of sarcocysts developed in the muscles of monensin-treated calves, monensin may have an ameliorating effect on acute sarcocystosis.