Crude protein levels for bull beef

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 old There 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.

The Problem:

Feedstuffs rich in protein tend to be more expensive then energy rich feedstuffs and consequently add to the cost of production by increasing feed costs. Any reduction in the amount of CP fed without compromising performance will have positive effects on net margins. For example, if it is proven that 12% diets prove adequate for bulls from 250kg to slaughter compared to 16%, this could reduce feed costs per bull by £10 per head. Across the industry this could be worth £3 million (£10 x 300,000 cattle) per annum.

Project Aims:

• To determine the effect of feeding rations containing either 12%, 14% or 16% dietary crude protein (FW basis) on the performance of intensively finished Holstein bulls

Approach:

• There will be three dietary treatments: 12%, 14% and 16% CP as fed.  A total 48 cattle (pure dairy bulls) will be recruited onto the trial with 2 pens per treatment and 8 bulls per pen
• Group feed intake will be recorded
• Cattle will be double weighed at the start and end of the trial, and at 30 day intervals during the trial
• They will be selected for slaughter at target fat class 3 and commercially slaughtered

Deliverables:

Information on the intake, growth rate, carcase quality and financial returns from each diet will be compared and the results publicised in the press and in the scientific literature.