Two digestion trials were conducted by using five cattle to determine the ability of two lignin techniques to estimate in vivo dry matter (DM) digestibility. The lignins investigated were, 1) acid detergent fiber extraction followed by digestion with 72% sulfuric acid (ADL), and 2) ADL procedure followed by hydrolysis with 3% sulfuric acid in an autoclave (121°C) for 1 hour (ADLAC). In trial 1, each cattle received 15, 2 and 1kg/d of corn (whole crop) silage, cubed alfalfa hay and concentrate, respectively. In trial 2, they were given 15 and 3kg/d of corn silage and cubed alfalfa hay, respectively. Digestion coefficients of DM from ADL ratio were higher than in vivo coefficients, but digestion coefficients from ADLAC ratio were similar to in vivo coefficients. Fecal recoveries of ADL and ADLAC were 111 and 92%, respectively, in trial 1 and 116 and 98%, respectively, in trial 2. ADLAC was more acceptable than ADL for use as internal markers in corn silage-alfalfa hay diets.
