The use of barley and a protein supplement such as soya bean meal as an ad libitum ration for intensively finished male beef calves has been well established and widely used since the conception of the cereal beef system in the 1960’s (Preston et al 1963). Rations on commercial beef units rearing Continental cross Holstein beef cattle are usually formulated to contain 175g CP/kg DM. With the recent fall in the price of barley there is increased interest in the cereal beef system for bull calves and late maturing Continental cross Holstein heifers. Increasing the proportion of barley in cereal beef rations can reduce ration costs and provided productivity is maintained, increase profit. There is also a paucity of information on the performance of heifers on the cereal beef system. The objective of this study was to evaluate feeding cereal based rations containing either 140 or 175g CP/kg DM to Continental cross Holstein bulls and heifers.