Effect of dietary crude protein level on the performance of cereal fed Holstein bulls

Abstract

Cereal fed Holstein bulls weighing 280kg were reared through to slaughter at Harper Adams University College on rations containing 12%, 14% and 16% crude protein (as fed).Overall the bulls recorded performance that either achieved or exceeded recognised targets for cereal beef production, recording DLWG's of 1.32-1.34kg to slaughter weights of 542-557kg at 13.4-13.8 months oldThere were no significant differences in DLWG, carcase daily gain, slaughter weight or carcase weight between the treatments. It is noted that highest the slaughter and carcase weights were achieved by the bulls fed the 12% ration however this was not statistically significant.The bulls reared on the 12% diet recorded the highest margin over feed costs and highest gross margin per bull. Reducing the protein content of the ration from 16% to 12% increased the gross margin per bull by 10.2% (£7.60 per bull).From the experiment it can be concluded that increasing the protein content of the ration above 12% for 280kg bulls does not improve physical or financial performance. Effect of dietary crude protein level on the performance of cereal fedHolstein bulls