Digestible Organic Matter (DOM)
Definition
In the Digestible Organic Matter (DOM) the amount of organic matter in a feed material is determined by reducing the amount of dry matter by the amount of inorganic matter (crude ash). The amount of organic matter is then multiplied by its digestion coefficient (Digestibility Coefficient of Organic Matter %).
Digestible Organic Matter thus indicates how many grams of organic matter per kg of dry matter a cow digests.
Composition and factors influencing DOM
Most of the Digestible Organic Matter consists of fermentable organic compound. The other part mostly consists of rumen ungradable protein, rumen bypass starch and fat.
A high crude ash content gives a lower content of organic matter and therefore Digestible Organic Matter. Contamination with sand will therefore lead to a lower Digestible Organic Matter content, despite high digestibility.
