Despite little published research data (Ekström et al., 1966) the use of crimped cereal grain in the rations of high producing dairy cows has gained considerable acceptance. This is partly due to an earlier harvesting date permitting replanting up to three weeks earlier and to reduced storage costs. However, the main attraction is that high levels of crimped grain are readily consumed without apparently adversely affecting rumen fermentation. Although this appears to be in direct contradiction with the belief that crimped grain is fermented faster due the ensiling process, this information was probably obtained using the in sacco technique which tends to over-estimate processed cereal degradation due of fine particulate losses (e.g. starch granules). This study was therefore undertaken to characterise the degradation profile of crimped wheat grain relative to that of conventionally harvested material.