CHANGES IN PROTEIN FRACTIONS OF EWE’S MILK THROUGHOUT LACTATION

Abstract

Seven ewes were milked weekly for a period of 12 weeks following parturition. Milk proteins were partitioned and changes in the concentration of each fraction were determined. Casein and non-protein nitrogen fractions increased during the first week while β-lactoglobulin, globulins and proteose-peptones decreased and α-lactalbumin remained unchanged. Following the first week of lactation, casein remained constant, β-lactoglobulin and non-protein nitrogen increased while globulins, proteose-peptones and α-lactalbumin decreased slowly until the end of the lactation period studied. Albumins and globulins constituted 15.0% of total nitrogen. Casein was equivalent to 75.2% of total nitrogen and crude proteins to 27.7% of the milk dry matter.