Efficacy of intramammary treatment with procaine penicillin G vs. procaine penicillin G plus neomycin in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria--a double blind field study.

The efficacy of intramammary treatments containing procaine penicillin G alone (treatment A) or a combination of procaine penicillin G and neomycin (treatment B) was compared in treating clinical bovine mastitis caused by gram-positive bacteria susceptible in vitro to penicillin G. Both treatments were supplemented with a single intramuscular injection of procaine penicillin G on the first day of treatment. The study was carried out using a double blind design on commercial dairy farms in Southern Finland. A total of 56 quarters were treated with treatment A and 61 with treatment B. The cure rates for both treatments were equal, which suggests that the use of the penicillin G-aminoglycoside combination does not increase the efficacy of the treatment over that achieved by using penicillin G alone in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria.