Percentage (%) of calves from which M. haemolytica, P. multocida, and/or H. somni were recovered at 1DOF, 13DOF, and 36DOF for (a) 2020 pen cohorts that received tulathromycin metaphylaxis, (b) 2021 pen cohorts that received tulathromycin metaphylaxis, and (c) 2021 pen cohorts that received oxytetracycline metaphylaxis. Samples at 1DOF were collected during on-arrival processing and before metaphylaxis. Percentages displayed are population-averaged with 95% confidence intervals, adjusted for clustering at the pen level using mixed effects logistic regression. For pen 16, sampling at 30DOF, prior to mass treatment, was used for analysis.