The acreage of maize grown for silage in Ireland has increased in the last few years. This study is concerned with determining it's feeding value relative to grass silage. If energy content is used as the indicator of feeding value, net energy values must be used to allow valid comparisons between feedstuffs. Therefore relative net energy values were calculated for grass and maize silage. However maize silage has very good intake characteristics and this needs to be taken into account in assessing it's value. Relative intake values were calculated for the grass and maize silage's and these were combined with the net energy values to give an overall feeding value.