The Variation in the Composition of Milk During Successive Stages of Milk Removal from the Mammary Gland of the Cow

Abstract

The composition of milk samples obtained during the milking period and following the injections of oxytocin has been determined in an attempt to elucidate the role of the epithelium of the ducts and cisterns in milk secretion. The results showed that the concentration of sodium and chloride in whey increased up to 29% with the successive samples, while the concentration of lactose, citrate, phosphate, calcium, and magnesium in whey and protein, calcium, and magnesium in skim milk decreased 12-24%. The concentration of potassium did not alter significantly during the course of the experiments. The possibility that sodium, chloride, and water are absorbed as milk passes through the ducts and cisterns is discussed.