[Age changes in the composition of immunoglobulins in cattle].

The electrophoretic and immunochemical methods as well as gelfiltration through Sephadex G-200 showed that there are no immunoglobulins in blood serum of fetuses and new-born calves. Specific proteins in a zone of gamma-globulins electrophoretic mobility which correspond to Ig M and Ig A are found in the serum of calves 3 hrs after their feeding on colostrum. The content of these proteins reaches the maximum on the third day of life but at the age of three months it lowers up to minimum. On the third month after birth in the blood serum of calves there appears a new protein in a zone of gamma2-globulins mobility which correspond to Im G-main immunoglobulin of adult animals. An assumption is advanced that the protective functions of calves of the early age are found chiefly with immunoglobulins Ig M and Ig A.