Modeling digestibility dynamics in leaf segments in a grass: a new approach to forage quality changes in a growing plant

Abstract

A model which describes the dynamics of dry matter digestibility (DMD) in leaves (laminae) in a grass was developed. The model treats the leaves of the plant as a set of 2-cm-long segments, and simulates DMD dynamics of the segments individually from their emergence through ageing. Each segment has its own initial DMD at emergence, and the DMD declines as the segment ages. The emergence and ageing of the segments are synchronized with the appearance and extension of individual leaves of the plant. The model was parameterized and validated against data from bahia grass ( Paspalum notatum Flügge). This new approach increases the mechanistic aspects of previous empirical models and is useful in developing our understanding of DMD dynamics in a growing plant. Furthermore, the approach presents a possible way to predict forage quality at a level of a bite of a grazing animal.