Dry Matter is the amount of feed remaining after evaporation of all its water content. Hose feeds vary enormously in their water content so, for example, fresh pasture may have a DM of 20% whereas oats may be almost 90% DM. In order to compare nutrient levels between different feeds the nutrient concentration is expressed in terms of Dry Matter. The alternative is to describe nutrient content as the concentration before removal of water or ‘’As Fed’.
So, Fresh Pasture at 20% DM with Protein As Fed of 4% would have Protein of 4 x 100/ 20 = 20% DM