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An evaluation of prediction equations incorporated in a computer program to ration beef cattle

Published online by Cambridge University Press:  02 September 2010

H. D. St C. Neal
Affiliation:
AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead SL6 5LR
M. Gill
Affiliation:
AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead SL6 5LR
J. France
Affiliation:
AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead SL6 5LR
A. Spedding
Affiliation:
Meat and Livestock Commission, PO Box 44, Queensway House, Bletchley MK2 2EF
S. Marsden
Affiliation:
Dalgety Agriculture Ltd, Dalgety House, The Promenade, Clifton, Bristol BS8 3NJ
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Abstract

Equations for the prediction of forage dry-matter intake, metabolizable energy (ME), rumen degradable protein and undegraded protein, based on those in the current Agricultural Research Council system, were incorporated into a computer program designed to be used by livestock advisors for on-farm rationing of beef cattle. The predictions of silage intake and live-weight gain are compared with experimental data.

Voluntary intake of grass silage was generally over-estimated by the program by proportionately at least 0·06, with a root mean square error of ±0·18 of the mean observed silage intake for the all-silage rations. The prediction of ME requirement for observed production had an error of +0·15 of average ME intake but the calculations of ME intake were themselves dependent on the predictions of the ME concentrations of the silages and supplements. Similarly the comparison of protein supply with requirement was highly dependent on the value assigned to N-degradability. However, the program can be used to assess how changes in the input values would affect ration formulation.

The mathematical basis of the program is described in the Appendix.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1988

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