Grass silage is an important feed for ruminants but it is well established that the voluntary food intake (VFI) is less than that of the same crop fed fresh or dry (Harris and Raymond, 1963). This effect has been associated with factors such as the products of ensiling as well as the asynchrony of nutrient release in the rumen. The objectives of the current experiment were to investigate whether the pattern of nutrient release in grass silage is a major factor contributing to its low intake and whether altering the pattern of nutrient release through supplementation would alter hourly and daily intake.