Selenium (Se) is a trace element of large importance owing to its implications in many metabolisms both in animals and in humans. Se participates in the antioxidant protection of cells and shows profound effects on health as e.g. cancer protection, antiviral effect, cardiomyopathy prevention,… in men (see review by Lyon et al 2003) and as prevention of metritis, mastitis or myopathies in cattle (Jukola et al, 1996). There are areas -Belgium e.g.- in which the Se content of feedstuff for cattle is rather low. Se is available for plants from the soil. The aim of the present work was to increase the Se content in grass silage and winter barley using Se enriched fertilizers for young growing bulls.