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Efficiency of energy utilization in cattle given food ad libitum: predictions according to the ARC system and practical consequences

Published online by Cambridge University Press:  02 September 2010

B. J. Tolkamp  and
J. J. M. H. Ketelaars
B. J. Tolkamp
Affiliation:
Department of Tropical Animal Production, Wageningen Agricultural University, PO Box 338, 6700 AH Wageningen, The Netherlands
J. J. M. H. Ketelaars
Affiliation:
Centre for Agrobiological Research, PO Box 14, 6700 AH Wageningen, The Netherlands
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Abstract

Overall efficiency of energy utilization (i.e. total net energy intake as a fraction of metabolizable energy intake) in cattle given food ad libitum was calculated from information included in the United Kingdom energy evaluation system as published by the Agricultural Research Council. For growing cattle (live weight 250 kg), overall efficiency was estimated for five levels of diet metabolizability (ranging from q = 0·45 to q = 0·65) for each of two diet types: coarse/long roughage and fine/pelleted diets. The overall efficiencies varied from 0·58 to 0·62 and were not systematically affected by diet type or diet metabolizability. For lactating cattle (live weight 600 kg), overall efficiency was also calculated for five diets with metabolizability ranging from 0·45 to 0·65. Calculations were made for cows at equilibrium intake (i.e. zero energy balance) and at milk production levels proportionately 0·30 higher or lower than those attained at equilibrium intake. Overall efficiencies varied from 0·60 to 0·63 and were not systematically affected by diet metabolizability.

It is concluded that, in practical cattle production systems with ad libitum feeding, the net energy content of food may be estimated at 0·6 of the metabolizable energy content (or 0·5 of the digestible energy content), irrespective of diet type, diet metabolizability or productive function.

Keywords

cattleenergyfood intakegrowthlactation
Type
Research Article
Information
Animal Production , Volume 59 , Issue 1 , August 1994 , pp. 43 - 47
Copyright
Copyright © British Society of Animal Science 1994

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References

Agricultural Research Council. 1980. The nutrient requirements of ruminant livestock. Commonwealth Agricultural Bureaux, Farnham Royal.Google Scholar
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Ketelaars, J. J. M. H. and Tolkamp, B. J. 1992b. Toward a new theory of feed intake regulation in ruminants. 3. Optimum feed intake: in search of a physiological background. Livestock Production Science 31: 235–258.Google Scholar
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