A Model of Digestibility Dynamics in Leaf Segments in Grass Swards

A mechanistic model which describes the dynamics of dry matter digestibility (DMD) in leaves in a grass sward was developed. The model treats the leaves in the sward canopy as a set of 2 cm-long canopy components, and simulates DMD dynamics in the components from their emergence through aging. Each component has its own initial DMD at emergence, and the DMD decreases as the component ages. The model was parameterized and tested against data from a bahiagrass (Paspalum notatum Függe) pasture. This new, mechanistic approach was proved to be useful in developing our mechanistic understanding of DMD dynamics in a growing plant. The model is considered to be of use as a part of an integrated model of sward canopy structure which can be used to simulate herbage intake of a grazing animal at a level of a bite.