Note on the composition of a fluid obtained from the udders of virgin heifers

Abstract

The secretion of milk by the mammary glands normally follows a period of pregnancy, but numerous cases have been cited in the literature of secretion which takes place in animals that have never borne young. Non-pregnant bitches frequently secrete milk several weeks after oestrus (1), and a secretion, apparently similar to milk, takes place after pseudo-pregnancy in rabbits (2). No quantitative analyses have been made of these secretions to show whether they possess the characteristics of true milk or colostrum.