Combinations of three challenge species in each study were used to differentiate areas of the intestines infected by the parasite. Groups were medicated 2 days before infection was administered. The safety of the 2 drugs when used in combination was demonstrated in the noninterference battery and coccidial challenge studies described in this document. In each of the several studies there was no evidence that drug was the cause of any mortality or toxicity. Based on the data in the parent NADAs and from the noninterference battery and anticoccidial challenge studies, the combination is safe to be fed to broiler chickens as indicated on the label.
Total residues are highest in liver tissue.
Drug residue elimination and assay noninterference studies were conducted to establish that each drug in the presence of the other does not exceed its established safe concentration of tolerance, as applicable, at the proposed withdrawal time and that neither drug interferes in each other's tissue residue assay. The analyses of these samples by the chlortetracycline microbioassay procedure showed quantitative recovery of chlortetracycline either in the presence or absence of salinomycin plus roxarsone. The medicated group was switched on the morning of Day 42 to unmedicated control diet, and birds were sacrificed following drug withdrawal periods of 0 to 7 days. Tissues from chickens receiving unmedicated feed during the entire study served as controls with tissues being collected on day 42 of the study. Kidney tissue was not assayed, as chicken kidney is no longer considered to be an edible tissue.