[Serum selenium levels in sheep from birth to 90 days of age].

The results of the study of the dynamics of selenium in the blood serum were compared in 31 piglets from birth to the age of 90 days. The analyzed selenium values in the blood serum immediately after birth (0.14--0.20 ppm) provide evidence of the intra-uterine placental passage of selenium. In the period of colostral and milk nutrition, the serum concentrations of selenium showed a statistically insignificant variation, followed by an abrupt drop of the level of the microelement in the weaning period (60th day). The individual values in this period ranged from 0.08 to 0.12 ppm. Towards the end of the study, the level of selenium in the blood serum of the piglets returned to its initial value; this indicates that although the critical period connected with weaning has a transient nature, it should be averted for preventing the occurrence of a selenium-deficit disease; this can be done by adding a supplement of 0.2% solution of sodium selenate or a combined preparation of selenium and vitamin E-Selevit.