D-вітамінний статус корів та їхніх телят у ранній постнатальний період у зимово-стійловий період

Abstract

The article presents data about the content of active metabolite of vitamin D3 – 25OHD3, calcium (total, bounded with protein and ultrafiltrated), inorganic phosphorus, magnesium and alkaline phosphatase activity and its isoenzymes in the blood of cows and their calves in the early postnatal period.Studies were conducted in the cows of the Ukrainian Black-and-White dairy breed and calves obtained from them. The experiment was performed during the winter housing period in pilot farm «Pasichna» of Institute of forage and agricultural Podillya NAAS of Ukraine, located in the natural geographical areas of Podillya. The blood for tests was collected from the jugular vein before morning feeding in the 5th−7th day since calving. The blood from the calves was collected in the following dates: at 5th−7th days old and at 28–30th days old. Vitamin D provision rate of animal organism was evaluated for the content of 25OH D3 concentration in blood. The level of 25-hydroxycholecalciferol is considered as a total reflection of the endogenous formation of cholecalciferol in the skin and its receipts from feed or vitaminpreparations. The concentration of 25ОНD3 in the blood of the examined animals was detected by means of the enzymelinked immunoassay using the test system developed by the Immunodiagnostik. The method is based on the competitive binding of 25OHD3 serum and 25OH D3-biotin with vitamin D3-binding protein (VDBP), that immobilized on 96-well immunological plates. The content of calcium (total, bounded with protein and ultrafiltrated), inorganic phosphorus, magnesium and alkaline phosphatase (ALP) activity were detected usingthe biological test kits produced by the Pliva Lachema firm (the Czech Republic). The performed research reported that the content of 25-hydroxycholecalciferol in serum of calves at 5–7-days age old was in the range of 29 to 34 nmol/l and slightly increased for the 28–30-days. It was established the dynamics of changes in the content of total calcium and its fractions, inorganic phosphorus, magnesium and activity of alkaline phosphatase and its isoenzymes in calves blood from 5–7- to 28–30-day-olds. The concentration of 25-hydroxyvitamin D3 in the blood of calves in the first days after birth was lower, and the concentration of calcium and inorganic phosphorus – higher compared with their values in the blood of mothers in the postpartum period. It was found that the activity of alkaline phosphatase in the calf serum was higher, compared with its value in the serum of mothers. The increase in activity of alkaline phosphatase in the calf serum is expressed to a greater extent due to its bone enzyme.