The different types of carbohydrate are classified according to the laboratory techniques used to assess them. ADF includes carbohydrate fractions soluble only in acid, principally the woody material Lignin, Cellulose and mineral ash from the plant cell walls. ADF affects digestibility of forage, the higher the ADF, the less digestible it will be. For hay ADF <35% is reasonable but >45% is poor quality and little nutritional value. ADF increases with plant maturity. See also NDF
