Effects of selenium (Se), supplemented by an injection under the skin on. In vitro phytohemagglutinin (PHA) -stimulated T blastogenesis. White blood cells was assessed in calves hybrids 45, 124, and 270 d of age, white blood cells in the blood (5 × 105) was received by the control (n = 4) and was treated Se (n = 4. ) stepbrother with 0, 0.4 and 0.8 micrograms PHA and 0.5 μCi [3H] -thymidine in a complete culture medium. The culture 60H total harvest volume of thymidine levels of blastogenesis. PHA stimulated lymphocyte or show a stimulation index (SI) has been evaluated for the treatment and the effects of age. In the attack, and the end of the trial period, plasma Se and concentration of glutathione in the blood peroxidase revealed that younger drivers [0.045 ppm and 48.4 units / g of hemoglobin (Hb), respectively]. It is a little calf deficiency and treated (0.075 ppm and 143.0 units / g of Hb, respectively) have sufficient status Se the SI was not influenced (P> 0.01) by treatment Se but was affected (P