Plant fiber (NDF) is the major source of potentially digested nutrients for ruminants, and variations in NDF digestibility are a major factor determining feed quality, especially that of foragers. The NDF consists of two conceptual entities: potentially digestible NDF (PDF) and indigestible NDF (IDF). Being indigestible, the level of IDF in the feed is an important predictor of feed quality, albeit negative. Thus, digestibility of PDF determines the digestibility of NDF. Additionally, IDF is nutritionally important as an indigestible natural plant marker intrinsic to the feed that can be used to estimate digestibility of PDF and other analytically definable feed entities. Because of the dynamic physical and chemical interactions involved in ruminal microbial digestion (hydrolysis) of PDF, one must distinguish between conceptual and analytically definable entities of PDF and IDF in their application to ruminant nutrition.
Was this article helpful?