Effect of Deoxyribonuclease on the California Test for Mastitis

Abstract

Nucleated but not non-nucleated body cells added to normal milks were found to produce typical California Mastitis Test (CMT) positive reactions. Treatment of mastitie milks with commercial 5 × recrystallized deoxyribonuclease but not ribonuclease or trypsin was shown to prevent the formation of gels characteristic of a positive CMT. Treatment of gels formed by the reaction of mastitic milk with DNAase but not RNAase or trypsin resulted in almost instantaneous dissolution of the gel. A level of 1.65 μg DNAase/ml of markedly mastitic milk (CMT-3+) was found to be sufficient to abolish the CMT reaction completely. These observations suggest that polymerized DNA originating from cells of the inflammatory exudate in mastitic milk is the component responsible for positive California Mastitis Test reactions. © 1962, American Dairy Science Association. All rights reserved.