Effects of Selenium Supplement Forms on the Diet-Cow-Calf Transfer of Selenium in Simmental Cattle

The aim of this study was to determine the efficiency of diet-cow-calf transfer of selenium (Se) depending on the forms of Se-supplement given to cows of Simmental breed during the last trimester of pregnancy and the first week of lactation. On day 195 of pregnancy the cows were randomly assigned to one of four experimental groups (n = 6), and the newborn calves belonged to the same group as their mothers (n = 6). The cows in the control group received diet without Se-supplement, while the supplemented groups received Se in equivalent doses in a powder form (Se-unprotected) or in a protected form (Se-protected) of sodium selenite or in organic compounds (Se-yeast), the calves received colostrum and milk from their mothers. The data about feed and Se intake, colostrum and milk daily production, Se concentration in colostrum, milk, and cows and calves blood serum were recorded. The diet-cow Se transfer efficiency was estimated as the following ratios: the concentration of Se in cows' serum after parturition/daily Se intake during prepartum; Se secretion in colostrum/daily Se intake during prepartum; and Se secretion in milk at 7 days of lactation/daily Se intake. The ratios were higher (P <= 0.02) in the Se-yeast group than in the other supplemented groups, in the Se-unprotected and Se-protected groups the ratios were similar (P > 0.05). The cow-calf Se transfer efficiency estimated as calves' serum concentration after birth/cows' serum concentration after parturition was similar (P > 0.05) in all experimental groups. The results showed that the form of Se supplement modulated the Se transfer from the diet to cows; Se was transferred more efficiently from the Se-yeast than from sodium selenite. The form of Se supplement did not affect the cow-calf Se transfer efficiency.