Immunological features of calf body

Abstract

The immune system, like any other body system, begins to form and develop during the prenatal period of an animal's life and in the postnatal period has a close relationship with other body systems. Cattle have their own peculiarities in the formation of the immune system and the formation of the body of a newborn animal in postnatal ontogenesis. During the antenatal (intrauterine) development of the fetus, the calf cannot receive protective antibodies due to the syndesmochorial structure of the placenta of cows. The first weeks of newborn calves’ life are a critical period for young animals, as calves are born agammaglobulinemic, the immune system is only developing and adapting, and a huge number of pathogens are looking for a way to penetrate the weak animal body. Postpartum immune protection of calves is mainly aimed at the innate nonspecific part of the immune system, and the development of passive immunity is stimulated by the consumption of maternal colostrum. Calves are born with a relatively developed cellular immunity, but an insufficiently developed humoral one which is compensated by the intake of immunoglobulins along with the colostrum of the mother, and thus colostral immunity is created. The bactericidal activity of blood serum is poorly expressed which is due to the absence of lysozyme in the blood of newborns and its deficiency in the colostrum of the first milk yields. Therefore, the newborn’s body is not capable of independent protection from pathogenic agents and for its protection during the first 5-7 days of life, passive transmission of maternal antibodies with colostrum is required. The review paper is devoted to the immunological features of calves of the early postnatal period as well as the characteristics of the immune system and its relationship with other body systems.