The results of this study indicate that feeding boars with diets supplemented with vitamin E is a practical method for optimising libido, servicing capacity and sperm viability in breeding sires. Boars receiving diets supplemented with 70 IU of vitamin E/kg feed had the shortest reaction time, highest number of mounts, combats, head-kicks, anogenital sniffs and optimum semen quality in comparison to boars receiving diets with 0 and 40 IU vitamin E/kg feed. It is recommended that routine checks be conducted to determine the Se levels in the serum of young pigs. More so, since vitamin E and selenium act synergistically, vitamin E supplementation does not completely eliminate the need for selenium in the diets of pigs.