MORPHOLOGICAL CHANGES OF BONE AND CARTILAGE TISSUE AND BONE MARROW OF NEWBORN CALVES AT DIFFERENT STAGES OF PRENATAL DEVELOPMENT

From the very beginning after birth, newborn calves have a different morpho-functional status, which determines their viability in the neonatal period, and is also a prerequisite for various serious diseases, which often end fatally. The skeletal system, as the central organ of immuno-genesis, performs an active function in the metabolism and manifestation of protective functions of calves. That is why its development is evidence of the viability of animals in the future for the entire period of their life. Thus, a sharp decrease in the viability of animals in the neonatal period is due to violations of the morphogenesis of immunocompetent structures and, above all, the skeletal system. The formation of bone organs in newborn calves has the appropriate ratio of parenchymal and stromal structures. In bone organs, the content of cartilage tissue, especially in growth zones, is more interconnected with the presence of osteoblastic bone marrow, and bone-red bone marrow. Compact and spongy bone substances are built from reticulo-fibrous bone tissue. In the bone marrow centers of bone ossification and bone marrow areas of the diaphysis of the tubular bones of the limbs, hematopoietic bone marrow prevails, among which there are single fat cells, or ïx clusters. The amount of cartilage in each bone depends on the position of the latter in the skeleton: the smallest content is in the tubular bones of the limbs, and the largest - in the rudimentary bones (coccygeal vertebrae, last rib), as well as in the sternum. The ratio of the content of bone, cartilage components and bone marrow in newborn calves indicates the degree of prenatal osteogenesis. The quantitative presence of bone marrow is determined by the structure of the spongy substance. Osteoblastic (bone-forming) bone marrow is observed in the primary spongy substance. And the presence of fat cells in the red bone marrow indicates the initial processes of its transformation. In order to prevent various pathological abnormalities in fetal development, antenatal monitoring of the course of pregnancy is necessary. Therefore, for early diagnosis and prevention of pathologies in the fetus, monitoring of the course of development is carried out, in accordance with the gestational age, using various research methods, and, in particular, X-ray and ultrasound examination.