The effect of lincomycin-neomycin treatment on experimental anaerobic bacterial bovine mastitis

Three healthy lactating quarters of a Friesland cow were each experimentally infected with a pure culture of a strain of either Bacteroides fragilis, Eubacterium lentum or a Peptostreptococcus sp. respectively. The onset and progression to clinical mastitis was monitored 12 hourly by examination for clinical signs of inflammation, bacterial culture, somatic cell counts and with a strip cup. All infected quarters developed clinical mastitis within 24 hours. The 2 quarters infected with B. fragilis and E. lentum respectively were treated 4 times consecutively at 12 hour intervals, commencing at 24 h by intramammary instillation of 10 ml of a mixture containing 200 mg lincomycin hydrochloride, 200 mg neomycin sulphate and 5 mg methylprednisolone (Lincocin Forte, Upjohn). Both quarters became clinically normal and no bacteria could be detected in the secretions 12 hours after the first treatment. At 36 hours the strip cup became negative, and the somatic cell count dropped to less than 500 X 10(3) at 72 hours after the initial treatment. The quarter infected with a Peptostreptococcus sp. was unable to overcome the infection by natural means when intramammary treatment was delayed for the first 36 hours after the onset of clinical mastitis. Subsequent treatment of this quarter gave results similar to those treated earlier.