Due to the significance of forage maize in Austrian cattle feeding systems, an experiment was carried at LFZ Raumberg-Gumpenstein (Styria, Austria), testing the rumen degradability of corn silage. The aim of the project was to evaluate the influence of variety, stage of maturity and year on composition and rumen dry matter degradability of stover, cob and whole plant. For this reason nine different varieties of maize were planted for three years and harvested at three different stages of maturity. After harvest stover and cob were ensiled separately and proximate as well as detergent analysis were carried out. Rumen dry matter degradability was determined using four steers and the in situ method. All factors have a significant impact on the proportion of cob in the whole plant and on the content of dry matter in stover, cob and whole plant. The factor year has a significant effect on the content of all proximate fractions in the stover, while variety only influences the content of XL and ADL and the maturity stage affects the content of XL, XP and ADL in this plant fraction. Year and maturity stage have a significant impact on most proximate fractions and fibre components in the cob and the whole plant. Variety only influences the content of XP and XL in the cob as well as the proximate fractions and the content of ADF in the whole plant. Variety, maturity stage and year have a significant impact on the potential and effective degradability of the stover. Variety and maturity stage also have a significant influence on the rumen degradability of the cob, while factor year showed no significant impact. The effective degradability of the cob is influenced by maturity stage and year, regardless which passage rate is used. The variety only has an impact on effective degradability, if the passage rate is low (2 % per h). All factors show a significant influence on effective degradability of the whole plant, while the potential degradability is only influenced by variety.