Cereal grains provide the major source of energy for ruminants in intensive production systems. Starch digestion in the rumen appears to be determined by the rate at which both the endosperm cell walls and, more importantly, the protein matrix surrounding the granule can be disrupted by enzymes than the properties of the starch itself. The presence of phenolic compounds influence seed coat digestibility and could interact with the protein matrix to affect starch digestibility. While processing and mastication are sufficient to disrupt these barriers, the rapid fermentation of starch in the rumen is not considered desirable as it can adversely affect animal health (e.g. acidosis) or via a lowered rumen pH inhibit fibre digestion. Processing methods are also criticised in terms of cost relative to inexpensive grain, and environmental issues e.g. alkali loss. A largely unexplored strategy to improve grain digestibility is pre-feeding treatment with exogenous enzymes. In this respect the potential of enzyme preparations, that cleave side-chain linked phenolics, to improve grain digestibility was examined in this study.