Effect of selenium fertilization on selenium in feedstuffs and selenium, vitamin E, and beta-carotene concentrations in blood of cattle.

Selenium (n = 56), total vitamin E, and homologues of natural vitamin E in feedstuffs (n = 52) and the concentrations of Se (n = 241), vitamin E (n = 244), and beta-carotene (n = 227) in blood were measured. The mean (+/- SD) Se content in hay, grass silage, oats, and barley produced using fertilizers enriched with Se was 0.13 (+/- 0.169), 0.17 (+/- 0.704), 0.23 (+/- 0.107) and 0.21 (+/- 0.119) mg/kg of DM, respectively, and the mean (+/- SD) vitamin E contents, calculated as dl-alpha-tocopherol acetate equivalents, were 39.7 (+/- 13.0), 120.0 (+/- 40.27), 24.4 (+/- 3.83) and 34.5 (+/- 3.57) IU/kg of DM, respectively. The mean Se concentrations in whole blood of cows, heifers, bulls and calves fed hay (n = 62), silage (n = 111), or pasture (n = 68) varied from 183 to 244 micrograms/l. The mean concentrations of total vitamin E in serum of lactating cows fed hay (n = 21), silage (n = 29) or pasture (n = 26) were 2.8 (+/- 1.43), 6.5 (+/- 3.03) and 8.2 (+/- 2.64) mg/l, respectively. For calves, concentrations of vitamin E in serum were as low as 0.25 mg/L. The mean concentration of beta-carotene in serum of lactating cows fed grass silage (n = 26) or pasture (n = 28) was 13.7 (+/- 6.61) and 15.4 (+/- 6.15) mg/L, respectively, but, in lactating cows fed hay (n = 20), concentrations were 2.5 (+/- 1.07) mg/L.