The number of studies related to detailed characteristics of immune system development in early stages of ontogenesis are directed to expansion of concepts of mechanisms of inherent and adaptive immunity in premature newborns. However, discrepancy in publication data and absence of clear conceptions about unique features of immune system in newborn piglets for different gestation periods have significant actuality for further investigation. The study was carried out to establish characteristics of phenotypic and functional characteristics of the immune cells and establishment of adaptive immunity in piglets. The antibody repertoire of sow has interested immunologists for decades, in part because of the ease with which large quantities of high affinity antibodies can be observed in serum, and into other fluids because of the presence of genetic variants for both light and heavy chain of all known immunoglobulin types. The integrative analysis of the cellular and humoral immunity in piglets during early ontogenesis carried out to clarify the exact mechanisms of the immune response modulation. Effectiveness and selectivity of the immunotropic chemicals application to regulate immune cell populations in piglets is presented. The progress in immune cell populations is regulated by the various cytokines production in the universal concentration-dependent manner. Furthermore, the development of the immune functions cross reacts with innate immunity mechanisms including anti-bacterial enzymes, epithelial barrier integrity in the both skin and intestine. The interaction between multiple components of innate immunity is a critic initiator of the dynamic changes in adaptive immunity. The natural resistance targets to the establishment of infection root and delays disease progression. The duration of the exposure to colostrum in important role in the dynamics of immune response as well as its efficacy. The chapter discusses the plural mechanisms so far proposed to be responsible for the modulation natural resistance.