Offered Papers Theme A: Efficient Production from Grassland
Description
Dry matter intake (DMI) of forages is often estimated as a reciprocal function of fibre concentration: DMI = fibre intake capacity / dietary fibre concentration (Mertens, 1987). This theoretical relationship is based on the concept that consumption of forage diets is limited by fill and that fibre represents the bulk of forage diets. This model, however, does not account for differences in DMI which should occur among forages with similar fibre concentrations but differing fibre digestibility. To account for these differences, we proposed an intake model where DMI is a reciprocal function of indigestible fibre concentration: DMI = c / CI, where c = intake capacity for indigestible fibre and CI is the concentration of indigestible fibre. This model assumes that livestock consuming forage diets of similar physical form but differing digestibility will consume a constant level of indigestible fibre. It applies only when DMI intake is regulated by fill and is not affected by digestible protein or energy concentrations. Since true DM digestibility is the inverse of indigestible fibre concentration, true digestible DM intake can be estimated as DDMI = c(1 - CI)/CI.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Predicting Intake from Indigestible Fibre
Dry matter intake (DMI) of forages is often estimated as a reciprocal function of fibre concentration: DMI = fibre intake capacity / dietary fibre concentration (Mertens, 1987). This theoretical relationship is based on the concept that consumption of forage diets is limited by fill and that fibre represents the bulk of forage diets. This model, however, does not account for differences in DMI which should occur among forages with similar fibre concentrations but differing fibre digestibility. To account for these differences, we proposed an intake model where DMI is a reciprocal function of indigestible fibre concentration: DMI = c / CI, where c = intake capacity for indigestible fibre and CI is the concentration of indigestible fibre. This model assumes that livestock consuming forage diets of similar physical form but differing digestibility will consume a constant level of indigestible fibre. It applies only when DMI intake is regulated by fill and is not affected by digestible protein or energy concentrations. Since true DM digestibility is the inverse of indigestible fibre concentration, true digestible DM intake can be estimated as DDMI = c(1 - CI)/CI.
