For routine use in cows at drying off, to treat existing intramammary infections and to assist in preventing new infections occurring during the dry period. It also aids in reducing the incidence of summer mastitis in dry cows and heifers at risk. Amongst the organisms found to be sensitive to Ampicillin and Cloxacillin are Streptococcus agalactiae, Streptococcus spp.,Staphylococcus spp, Corynebacterium spp and Escherichia coli.