The dissertation is devoted to the study of the safety of body of cattle with vitamin D and its effect on metabolism depending on age, physiological state, level of productivity and period of the year. The dependence of 25OHD3 level in calves blood in the early postnatal period was established on the level of this metabolite in the blood of cows in the last days of calving and after calving.
The features of vitamin D3 metabolism and manifestation of its functional activity at different doses and methods of introduction into the parameters of mineral, lipid and protein metabolism in cows of different levels of milk productivity and physiological period, as well as calves obtained, have been determined.
In the experiment it was proved that intramuscular administration of vitamin D3 cows in physiologically substantiated doses in the last days of calving and after calving, as well as daily oral administration of cholecalciferol during the month is accompanied by an increase in the blood of cows and their calves containing 25ОНD3, total calcium and its fractions, Phosphorus of inorganic, magnesium, total lipids, phospholipids and cholesterol and alkaline phosphatase activity, which is expressed more to the higher dose, as well as parenteral administration. The expediency of using cholecalciferol as a means of correcting D vitamin status, mineral, lipid and protein metabolites in critical physiological periods of cows and their offspring has been established.
In the dissertation on the basis of monitoring studies, seasonal features of the degree of vitamin D supply of cows in the 4th month of lactation and its influence on mineral, lipid and protein metabolism parameters depending on the conditions of dairy cattle breeding were established.
Corrective effect of vitamin D3 on metabolic processes in young cattle in the period of formation of scarring, puberty and physiological maturity is substantiated. It has been shown that the parenteral administration of cholecalciferol in the course of a month in the winter-spring period of the stool exhibits long-term regulatory effects on D-vitamin status, mineral, lipid and protein metabolism and depends on the level of 25OHD3 in blood of the heifers prior to the administration of the drug, dose and time after termination Its introduction.
A series of new data on the intensity of synthetic and energy processes in skeletal muscle of calves in vitro was obtained, and the efficiency of administration of cholecalciferol alone and in combination with retinol and tocopherol on the metabolic profile of blood calves in the period from milk to cicatricial digestion has been proved.
For the first time new data have been obtained that postpartum hypocalcemia is accompanied by a violation of mineral, lipid, protein and energy metabolism, which is manifested by a decrease in total calcium content, ultrafiltrated calcium, phosphorus inorganic, calcitonin, phospholipids, cholesterol, mono- and polyunsaturated fatty acids (oleic and nerve, linoleic and arachidone), total protein and glucose, and increased 25 OHD3, NEFA, saturated fatty acids (myristic, margarine) and the activity of AsAT and AlAT in the blood of cows.
In the dissertation on the basis of experimental researches it was proved that 3-5 days before calving in the blood of cows that are susceptible to the disease, the content of 25OНD3, total and ultrafiltrated calcium, inorganic phosphorus, magnesium, total protein and calcitonin decreases and the level of non-esterified fatty acids increases and Activity of alkaline phosphatase. The corrective influence of parenteral administration of cholecalciferol on the normalization of metabolism in the period before calving and the prevention of postpartum hypocalcemia has been experimentally proved.
Thus, monitoring of the level of vitamin D (content 25ОНD3) and comprehensive biochemical studies can serve as a basis for clarifying the norms of cholecalciferol for cattle for different physiological conditions, the period of growth and development, and depending on the conditions of dairy cattle breeding. The results confirm the hypothesis that vitamin D3 affects the body as a whole and its individual tissues and cells, without limiting only the regulation of calcium and phosphorus homeostasis, but also extending to the metabolism of lipids and proteins.
