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On incorporating diffusion and viscosity concepts into compartmental models for analysing faecal marker excretion patterns in ruminants

Published online by Cambridge University Press:  09 March 2007

J. France ,
J. H. M. Thornley ,
R. C. Siddons  and
M. S. Dhanoa
J. France
Affiliation:
AFRC Institute of Grassland and Environmental Research, North Wyke Research Station, Okehampton, Devon EX20 2SB
J. H. M. Thornley
Affiliation:
Intitute of Terrestrial Ecology, Edinburgh Research Station, Bush Estate, Penicuik, Midlothian EH26 OQB
R. C. Siddons
Affiliation:
formerly AFRC Institute of Grassland and Environmental Research, Hurley, Maidenhead, Berkshire SL6 5LR
M. S. Dhanoa
Affiliation:
AFRC Institute of Grassland and Environmental Research, Plus Gogerddan, Aberystwyth, Dyfed SY23 3EB
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Abstract

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Deterministic mathematical equations are derived to describe the pattern of marker excretion in the faeces of ruminants under steady-state conditions when diffusion and viscosity concepts are introduced into a simple two-compartment scheme of the gastrointestinal tract. The basic scheme comprises a pure-mixing pool obeying first-order kinetics and a second compartment exhibiting streamline flow. Introduction of a velocity gradient, longitudinal diffusion or both into the second compartment, even with various simplifying assumptions, yields analytically insoluble equations. The impact of these mechanisms is to be investigated numerically rather than analytically in future work.

Keywords

DiffusionViscosityCompartmental modelsFaecal marker excretion patternsRuminants
Type
Modelling of Intestinal Flows
Information
British Journal of Nutrition , Volume 70 , Issue 1 , July 1993 , pp. 369 - 378
Copyright
Copyright © The Nutrition Society 1993

References

REFERENCES

Diem, K. & Lentner, C. (1970). Scientific Tables, 7th ed. Basel: Geigy.Google Scholar
Ellis, W. C., Matis, J. H. & Lascano, C. (1979). Quantitating ruminal turnover. Federation Proceedings 38, 2702–2706.Google ScholarPubMed
Faichney, G. J. (1975). The use of markers to partition digestion within the gastro-intestinal tract of ruminants. In Digestion and Metabolism in the Ruminant [McDonald, I. W. and Warner, A. C. I., editors]. Armidale, NSW: University of New England.Google Scholar
Fishenden, M. & Saunders, O. A. (1950). An Introduction to Heat Transfer. Oxford: University Press.Google Scholar
France, J., Dhanoa, M. S., Siddons, R. C., Thornley, J. H. M. & Poppi, D. P. (1988). Estimating the production of faeces by ruminants from faecal marker concentration curves. Journal of Theoretical Biology 135, 383–391.CrossRefGoogle ScholarPubMed
France, J. & Siddons, R. C. (1986). Determination of digesta flow by continuous marker infusion. Journal of Theoretical Biology 121, 105–119.CrossRefGoogle Scholar
France, J., Thornley, J. H. M., Dhanoa, M. S. & Siddons, R. C. (1985). On the mathematics of digesta flow kinetics. Journal of Theoretical Biology 113, 743–758.CrossRefGoogle ScholarPubMed
Grovum, W. L. & Williams, V. J. (1973). Rate of passage of digesta in sheep. 4. Passage of marker through the alimentary tract and the biological relevance of rate constants derived from the changes in concentration of marker in faeces. British Journal of Nutrition 30, 313–329.CrossRefGoogle ScholarPubMed
Krysl, L. J., McCollum, F. T. & Galyean, M. L. (1985). Estimation of fecal output and particulate passage rate with a pulse dose of ytterbium-labeled forage. Journal of'Range Management 38, 180–182.CrossRefGoogle Scholar
Mahler, H. R. & Cordes, E. H. (1966). Biological Chemistry. New York: Harper & Row.Google Scholar
Newman, F. H. & Searle, V. H. L. (1948). The General Properties of Matter, 4th ed. London: Arnold.Google Scholar
Nubar, Y. (1971). Blood flow, slip and viscometry. Biophysical Journal 11, 252–264.CrossRefGoogle ScholarPubMed