Transfer of Dietary Selenium to Milk

Abstract

Twenty-five lactating cows were used in groups of five to study the amounts of dietary selenium transferred to milk. Amounts of dietary selenium varied from deficient to five times the adequate concentration and ranged between 41 ppb and 828 ppb. Sodium selenite and brewers grains, a rich naturally occurring source of selenium, supplied supplemental selenium. Selenium in milk and plasma were related to the amount consumed, but the response was nonlinear since 4.8% of the added selenium was transferred to milk with a deficient diet but only .9% of the amount of added selenium was in milk of cows consuming diets adequate in selenium. Nineteen percent of the selenium furnished in brewers grains appeared in the milk when the ration was deficient in selenium. The small amounts of selenite selenium transferred from the diet to milk were too little (5.5 micrograms/kg) to be a potential hazard to human health when a diet containing .1 to .2 ppm of selenium was fed to dairy cows, an amount sufficient to meet the cow's dietary needs.

Selenium Metabolism in Cattle: Maternal Transfer of Selenium to Newborn Calves at Different Selenium Concentrations in Dams

“…A significant correlation (r = 0.78) between Se concentrations in blood of cows and calves, and also between milk Se concentrations in cows and Se concentrations in whole blood, plasma and even GSH-Px activity in erythrocytes in their calves (r = 0.59 -0.68) were demonstrated by Pehrson et al (1999). Although data on the relationship between dietary intakes of selenium and its concentrations in blood and milk are available (Conrad and Moxon 1979;Maus et al 1980;Grace et al 1997;2001) and milk selenium concentration assessments are used in the diagnostics of Se status (Koutník et al 1996;Grace et al 2001), our results lead us to believe that this method of deficiency diagnostics is questionable, at last in the period of colostrum production, because examinations of the cows in this study revealed only minimum differences in colostrum Se concentrations at widely different selenium concentrations in blood. Moreover, the form of selenium supplemented is also known to significantly influence Se concentration in milk: milk secretion levels of selenium supplemented in organic selenium is much higher those of inorganic selenium (Knowles et al 1999;Orthman and Pehrson 1999).…”

Effects of either sodium selenite or Se yeast (Sc CNCM I-3060) supplementation on selenium status and milk characteristics in dairy cows

“…Other research suggested that the inorganic forms widely used have a low availability (Binnerts and Viets, 1989). Indeed, in the earlier work of Conrad and Moxon (1979), the addition of selenium as sodium selenite to silage and grain, which were considered selenium deficient, resulted in 4.8% of added selenium being transferred to milk. Ortman and Pehrson (1999) concluded that it seems doubtful whether the concentration of Se in milk could be increased to a useful extent for human nutrition by supplementing cows with inorganic Se compounds without using doses that would exceed the legal limits of the US and European Union (0.3 and 0.5 mg Se kg − 1 dietary DM, respectively).…”

“…Very similar value could be estimated for the apparent transfer efficiency of the added dietary SeMet into milk of these animals (SY05), because the percentage of total Se comprised as SeMet in Se yeast was very similar to the percentage observed in milk (63% and 59% of total Se respectively). The earlier work of Conrad and Moxon (1979) observed that the addition of organically incorporated selenium in the form of brewers dried grains resulted in 19% of the dietary selenium being transferred to milk. Juniper et al (2006) using a basal diet of 0.15 mg Se kg − 1 DM, observed that 18% of added Se as Se yeast (using a diet containing 0.40 mg total Se kg − 1 DM) being transferred to milk in dairy cows.…”

Influence of Se status on milk Se concentrations in dairy cows

“…Selenium (Se) given orally or as an injection has been observed to increase Se concentrations in blood and milk of both sheep and cows (Jacobsson 1965;Grant & Wilson 1968;Jenkins & Hidiroglou 1971;Conrad & Moxon 1979;Maus et al 1980;Weiss et al 1990). Therefore when the Se intakes are low, Se supplementation of the dam will increase and maintain the Se status of both the A96047 Received 26 June 1996; accepted 13 November 1996 mother and offspring during pregnancy and lactation.…”