Intra-uterine absorption of sodium benzylpenicillin in the cow

Twenty-six experiments were performed on six healthy, non-lactating cows with normal oestrous cycles. Absorption of sodium benzylpenicillin from the uterus in oestrus and on day 12 following oestrus was compared with intravenous injection. Absorption, as shown in plasma from the uterus of six cows in oestrus, occurred to a greater extent (mean peak 12.80 ± S.E.M. 3.36 i.u./ml) than from the uterus in the luteal phase on nine occasions (mean peak 3.92±0.75 i.u./ml.). Intrauterine infusion of 10% Lugol's iodine solution before the administration of antibiotic did not significantly alter absorption on day 12 in six cases (mean peak 5.07±1.51 i.u./ml).