Milk proteinogram of the cows submitted to milk retention

Abstract

Diseases, breeding and production intensity, as well as inadequate handling were factors considered as stressful to milk cows, determining milk retention. Four healthy adult cows and in full milking period and without any prior mamits and/or intra-mammary treatment were experimentally submitted to 10% milk retention of which milk samples were collected at the following times: before milk retention, 12, 24, 36, 48, 60 hours during retention and 168 and 180 hours after the initial procedure, or being, 108 and 120 hours after retention ceased. The milk samples were previously submitted to physic-chemical and microbiological exams. The whey was obtained by milk coagulation with renin and the proteinogram determined by biuret method and fractionizing by polyacrymalide gel electrophoresis. A gradual and significant increase of some fractions of the whey was observed: serum albumin and immunoglobulin bovine, lactoferrin; ±1-antitrypsin; ²-lactoglobulin and; ±-lactoalbumin. At the end of the experiment, the proteic fractions returned to their initial state, the moment previous to the initial milk retention.