Protein and mixed forage beef

Experiment 1

• Performance of the British Blue x Holstein steers was very good with cattle being slaughtered at 16-17 months old with carcase weights of 340-350kg exceeding the recognised target for 18-month beef production systems
• Carcase weights were similar across the 4 treatments, however cattle on the forage based diets tended to take longer to reach slaughter weight hence DLWG and CDG showed a decline with increasing amounts of forage in the ration, but this however was not statistically significant
• Replacing cereals with WCW increased daily DMI, which partially compensated for the reduced energy density (M/D) of the diets, but resulted in a poorer FCR
• Diet costs were lowest with the WCW75 treatment; they were similar for the cereals and WCW50 and highest for the WCW25 treatment
• Margins were similar for the Cereals and WCW75, however lower for the WCW25 and WCW50     
• The earlier slaughter of the steers fed ad-lib cereals would result in a small reduction in variable and fixed costs, however the fixed costs for a forage based system would require silage clamps, a feeder wagon and materials handler which would be significantly higher than one based on feeding cereals from hoppers
• If farm resources are available to make, store and handle forage the replacement of 75% of cereals with well-made good quality high energy (25+% starch, 10.5+ME) whole crop should be considered
• The overall conclusion is that farmers should either finish cattle on either ad-lib cereal systems or consider replacing a significant proportion of cereals i.e. 75% with a high energy forage

Experiment 2

• Overall performance of British Blue x Holstein steers on all treatments was good with cattle being slaughtered at 18 months with carcase weights of 340–350kg, exceeding the targets for 18-month beef production systems
• Final liveweights (mean 650 kg) were similar for animals on all treatments, however, steers offered the three forage-based treatment took longer to achieve slaughter weight; consequently, daily LWG was 1.45, 1.39, 1.35 and 1.23 kg/day for steers offered diets C, WCW, RC33 and RC67 respectively
• Steers offered diet C had a higher KO% (53.4%) than those offered the three forage-based treatments (mean 52.6%); consequently, steers offered treatment C (355 kg) had a higher carcase weight than those offered the forage-based diets (mean 342 kg)
• Replacing cereals with 750 g/kg DM forage increased DMI from 9.38 kg/day for steers offered diet C to 12.16, 12.84 and 11.69 kg/day for steers offered diets WCW, RC33 and RC67 respectively
• The higher DMI intakes partially compensated for the reduced energy density (M/D) of the three forage-based diets, however, the lower daily LWG of steers offered diet RC67 suggests that the RC used had a lower ME content
• As a consequence of higher DMIs the feed conversion ratios of steers offered diets WCW, RC33 and RC67 were higher (8.78, 9.56 and 9.50 kg/kg respectively) than those offered diet C (6.45 kg/kg)
• Total diet costs were lowest for steers offered diet WCW (£255) followed by diet RC33 (£271) and diet RC67 (£279); diet C had the highest total diet cost (£289)
• Overall margins were similar for steers offered diets C, WCW and RC33 but slightly lower for steers offered diets RC67
• The results confirm those of experiment 1 that similar levels of physical and financial performance can be achieved by replacing up to 750 g/kg DM cereal-based concentrates with high quality fermented WCW silage. In addition, RC silage offers a viable alternative to vegetable protein supplements
• The cost effectiveness of different dietary strategies depends on the relative costs of forages and concentrates

The Problem:

High energy and protein forages have the potential to replace concentrates in dairy beef finishing systems. This may reduce production costs and the environmental impact of beef production, whilst increasing the nutritional value of beef. Protein is an essential nutrient in animal diets, and up to date information on appropriate levels of protein supplementation are essential to optimise animal performance. The objectives of the project will be to investigate the potential for replacing cereals and protein supplements in the diet of finishing cattle with high energy and protein forages, and re-evaluate the optimum level of protein required in the diet of growing cattle

Aims and Objectives:

Aims

Investigate the potential for mixed high energy and protein forages to replace concentrates in dairy beef diets during the finishing phase. Re-evaluate the optimum level of protein supplementation required in the growing phase by dairy bred native breed heifers.

Objectives 

1. To evaluate the replacement of concentrates with fermented whole crop wheat silage on the performance of 400 kg Continental cross Holstein steers during the finishing phase.
2. To evaluate the effect of dietary inclusion of fermented whole crop wheat silage with red clover silage on the performance of 400 kg Continental cross Holstein steers during the finishing phase.
3. To determine the optimum level of protein supplementation for dairy-bred native breed heifers fed grass silage based diets, during the growing phase.
4. To produce cost effective feeding strategies for dairy beef production systems based on home grown forages with minimal concentrate supplementation.

Approach:

Experiment 1

Effect of replacing cereal based concentrates with fermented whole crop wheat (WCW) for finishing British Blue-Holstein cross steers.

• 48 BBX steers at 400kg allocated to one of four treatments in a randomised block design
• Treatment 1 will be a conventional barley concentrate, treatments 2, 3 and 4 will be 75:25, 50:50, 25:75 DM ratio of concentrate: WCW silage respectively
• Performance will be measured; individual DMI, LW recorded at 30 day intervals to slaughter. At slaughter carcase weight, carcase pH, classification and liver damage scores will be recorded.

Experiment 2

Effect of the level of WCW silage with red clover silage inclusion on the performance of British Blue-Holstein cross steers.

• 48 BBX steers at 400kg allocated to one of four treatments in a randomised block design
• The forage component of the diet in treatment 1 will be 100% WCW, treatments 2, 3 and 4 will contain WCW:Red clover ratios of 66:33, 33:66, 0:100 respectively
• Animal performance will be measured as in experiment 1.

Experiment 3

Effect of increasing dietary crude protein levels in growing Angus-Holstein heifers fed grass silage based diets.

• 44 Native x Holstein heifers at 300kg will be allocated to one of 4 treatments
• Treatment 1, ad-lib grass silage supplemented to meet AFRC (1993) requirements for DLWG of 0.8kg/d, treatments 2, 3 ad 4 will consist of grass silage supplemented to supply 1.1, 1.2 and 1.3 times AFRC (1993) requirements respectively
• Animal performance will be measured; group intakes will be recorded, LW will be recorded at 30 day intervals. Animals will be followed through to slaughter where carcase weight, carcase pH and classification will be recorded.