NON-PERMEABILITY OF THE LACTATING BOVINE MAMMARY GLAND TO PENICILLIN

Abstract

Penisillin activity was not observed in any of several milk samples obtained in a 24-hr. period from a normal Jersey heifer following intraven. injn. of 10,000 units of penicillin in one trial and 500,000 units in a 2d trial. The samples obtained in the first 6-hr. period in the 2d trial were pooled and the cream and skimmed milk tested separately for penicillin. The cup method of assay was used, with Staph-ylococcus aureus H. as the test organism. No zones of inhibition were observed.