Variation of chemical composition data of agricultural and forest fibrous by‐products as determined by the two detergent systems of analysis

The growing use of agricultural and forest by‐products as ruminant feed, and of the detergent system to determine their feeding value, makes it of interest to compare direct and sequential detergent analyses in order to examine the differences between them and the extent of accuracy. The chemical composition of cereal straws (oat, barley, rye, wheat, maize) and legume straws (fenugreek, pea‐grass, lupin, pea and bean), grapevines, fenugreek bagasse and poplar bark was determined by applying both methods. Lignin (measured as permanganate lignin) and cellulose (measured as sulphuric acid cellulose) showed the greatest differences (2·0 and 3·2%, respectively). Tannins (1·5% of DM) and cell‐wall protein (2·0% of DM) could account for the discrepancy between both routines of analysis and for that between both lignin procedures.