Grain maize for finishing beef cattle

Results:

Bulls fed crimped maize grain had significantly faster daily live weight gains (1.51 v 1.34kg) and were slaughtered 13 days earlier. They also tended to produce heavier carcase weights and have better killing out percentages.

Total daily intake on a fresh weight basis were relatively similar however due to the lower dry matter content of the crimped maize mix (66% DM), total and daily dry matter intakes were markedly lower for the crimped maize fed bulls. The combination of faster growth rates and lower DM intake resulted in crimped maize fed bulls tending to show much improved feed conversion efficiency compared to the barley fed bulls.

No differences in either conformation or fat class were recorded between the groups.  In this study the presence of liver abscesses were assessed at slaughter as an indication of acidosis incidence.  The maize fed bulls recorded lower incidence of liver abscesses than barley fed bulls.

Crimped maize fed bulls recorded a higher margin over feed of some £32 per bull. Feed costs per kg liveweight gain were reduced by 10.4% (10p) and by 13.4% (22p) per kg carcase gain for the maize fed bulls compared to those fed the barley based ration.

The project also investigated the use of different additives on crimped maize and found that the crop could be ensiled successfully with or without an additive.  Using an additive was found to change the fermentation characteristics and the nutritional value of the crop according to the mode of action of the additive used.   In vivo digestibility studies confirmed that maize starch was of lower rumen degradability than barley starch.

Summary of results:

Planned Activity:

• The results of this work will be presented at the Maize Growers Association conference in February 2011 and at the British Society of Animal Science conference in April 2011.
• Farmer meetings will be organised to discuss the potential of all forms of maize in beef rations
• There will be a farmer meeting at Harper Adams to discuss the results of this study and other topics of relevance to intensive beef systems.  Organised for April 2011.
• Press articles will be drafted and placed as appropriate.
• Farmer literature will be produced under the BRP brand.

The Problem:

There is now growing interest in feeding grain maize to cattle due to its high energy (14.5 ME MJ/kg DM) and starch (71% in DM) content. A relatively high proportion (35%) of the starch is rumen undegradable compared to 15% for rolled barley which should help minimise problems with rumen acidosis.

Project Aims:

To determine the effect of feeding crimped maize to intensively finished Holstein and Continental cross Holstein bulls through to slaughter. In addition digestibility and rumen degradability of the experimental diets will be determined in sheep, as well as a separate study to evaluate ensiling characteristics of crimped maize.

Approach:

• In the performance study the bulls were housed in straw yards and fed either a control diet of 14%CP/kgDM concentrates or ad libitum crimped maize supplemented with soya bean meal, rapeseed meal and minerals (140g CP /kg DM).
• The whole tract digestibility of fermented grain maize was determined using male/castrate lambs. Lambs were offered either a basal forage diet or a mixed diet containing equal proportions of forage and grain maize to provide a maintenance level of feeding.
• The rumen degradability characteristics of fermented grain maize were determined using two wether sheep fitted with permanent rumen cannula using the in situ technique. Grain samples were incubated in the rumen for various time periods and the rate and extent of DM, CP and starch degradability determined.
• At harvest grain maize was either left untreated (control), or treated with one of four additives to evaluate ensiling characteristics.