title: On using a double-exponential model for describing faecal marker concentration curves.
abstract: A mathematical and numerical appraisal of the double-exponential model is presented, with particular reference to its ability to reproduce preset values of biological measures such as rumen and whole-tract mean retention times and faecal production rate. A complete, formal mathematical derivation is provided, with consideration given to a solution to the model when the two smallest rate constants are equal. It is concluded that any error introduced by using an approximation in deriving the double-exponential form is negligible in practice, and that the double exponential in logarithmic form is able to determine the relevant biological measures quite satisfactorily and speedily.
authors.affiliation: AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead, Berkshire, U.K.
authors.forename: M S
authors.initials: MS
authors.lastname: Dhanoa
authors.forename: J
authors.initials: J
authors.lastname: France
authors.forename: R C
authors.initials: RC
authors.lastname: Siddons
mesh_terms: D000821:Animal Feed; D000818:Animals; D015415:Biomarkers; D005243:Feces; D007700:Kinetics; D016014:Linear Models; D012418:Ruminants
chemical_list: D015415:Biomarkers