Barley Protein and Rapeseed Meal as Protein Supplements for Growing Cattle

Growing cattle on ad libitum hay- (H) or grass silage- (S) feeding were given supplements of barley (B), barley and rapeseed meal (BRSM) or barley and barley protein (BBP) in order to compare barley protein (BP), a by-product of integrated starch-ethanol production and rapeseed meal (RSM) as protein supplements for growing cattle. The protein intake was also calculated in terms of AAT (amino acids absorbed in the small intestine) and PBV (protein balance in the rumen). Both the BBP and the BRSM tended to have a positive effect on daily live weight gain (LWG) in the beginning of the experiment, below live weight (LW) of 250 kg. Above that LW protein supplementation did not effect on LWG. BP seemed to be more suitable as a protein supplement for H- than for S-based diets. The AAT-PBV system seemed to have advantages compared to the DCP system on S-based diets, the advantages being negligible on H-based diets.