Appropriate assessment of the contribution of antibiotic use in animal agriculture to development of antibiotic resistance in bacterial pathogens and development of efficient mitigation strategies are limited due to a lack of data on the elimination of antibiotics from animals. The objective was to investigate urinary disposition kinetics and fecal excretion of pirlimycin and cephapirin, 2 antibiotics commonly used on dairy farms as intramammary infusion. Three lactating cows were administered 2 doses of pirlimycin (50 mg/cow; 24 h apart), and 3 end of lactation dairy cows were administered cephapirin (1200 mg/cow) intramammary. Feces and urine were collected just before antibiotic infusion and at 2, 4, 8, 12, 16, and 24 h after 1st dose of pirlimycin, at 2, 4, 8, 12, 16, 24, 36, 48, and 72 h after 2nd dose of pirlimycin, and at 2, 4, 8, 12, 16, 24, 36, and 72 h post-cephapirin infusion. Antibiotics were quantified using UPLC-MS/MS. Urinary disposition kinetics parameters were derived by fitting urine concentration-time data into noncompartmental model. Elimination rate constants in urine were estimated using regression analyses of antibiotic concentrations after peak time. The elimination half-life, mean residence time, and elimination rate constant for 1st and 2nd dose of pirlimycin and cephapirin were 11.6 ± 3.6, 20.2 ± 8.8, and 14.9 ± 1.9 h, 22.1 ± 9.3, 33.1 ± 14.5, and 25.2 ± 4.9 h, and 0.039 ± 0.034, 0.038 ± 0.016, and 0.048 ± 0.006 h⁻¹, respectively. Fecal concentration of pirlimycin peaked (252 ± 162 ng/g) at 34.9 ± 9.2 h after the 2nd dose. Despite intramammary administration, antibiotics reached blood and the digestive tract, were excreted in urine and feces, and thus may influence microbial antibiotic resistance in the gut and following excretion. Slow elimination and long residence time of antibiotics indicate that manure may need to be treated to reduce antibiotic loading to the environment. The data obtained in this study will allow development of efficient manure management strategies to reduce the contribution of dairy farms to the challenge of antibiotic resistance.