[Content of soluble proteins in the mammary gland tissue of cattle]

During electrophoresis in agar-agar gel soluble proteins of cattle mammary gland are separated into 11-12 fractions, the amount of which changes essentially. In these proteins of heifers, cows with calf and dry nonlactating cows prealbumin is found. The amount of albumin is the highest in proteins of lactating cows (46%) and the total amount of immune globulins--in heifers (58-60%) and in cows with calf (52-62%). Changes in the amount of other fractions depend on individual peculiarities. The highest amount of soluble proteins in animals is observed at the second stage of pregnancy (6 g %). In the lactating cows and heifers it is 3 and 6 times lower, respectively, and in animals at the first stage of pregnancy and in nonlactating dry cows the amount of soluble proteins is almost the same.