Small-Sample in Vivo Cellulose Digestion Procedure for Forage Evaluation

Abstract

Summary Small samples of forage in nylon sacks were suspended in the rumen of fistulated cows to determine how the coefficients of cellulose digestibility obtained by this method compared with those obtained by conventional digestion trials. The cellulose digestion coefficient of 63.7% determined for Coastal Bermuda in a conventional digestion trial was not significantly different from the coefficient of 61.0% at the end of 72 hr by the small-sample method. Cellulose digestibility of average-quality alfalfa hay was 56.5% by conventional methods. This was not significantly different from the digestion coefficient (55.2%) determined by the small-sample method. Three fistulated cows were fed Coastal Bermuda hay and eight different hay samples were subjected to digestion by the small-sample method. A correlation of +0.83 was obtained when the 48-hr legume and 72-hr grass hay digestion coefficients were compared with results from conventional trials. Significant positive correlations between cellulose digestion measured by the two methods indicate that the small-sample technique used with a regression equation might provide a valid estimate of cellulose digestion.