Abstract
In the United States, about 50 million tons of wood and bark residues, containing up to 75% carbohydrate are available annually as a potential energy source for ruminants. Except for modest digestibility of a few hardwood species, however, the carbohydrates of whole-wood residues are essentially unavailable to the ruminant animal. The close molecular association between the major constituents of wood—cellulose, hemicellulose, and lignin—appears to limit bacterial and enzymatic access to the carbohydrates of the cell wall. Success in using wood residue carbohydrates as an energy source thus requires the development of an effective and practical means for enhancing the accessibility of the cell wall constituents to the action of rumen microorganisms. Of prime importance to this type of undertaking is a rapid, accurate, and inexpensive in vitro technique for assaying the large numbers of samples that will be generated. The in vitro procedure of Tilley and Terry (1963) or one of its modifications has been used extensively and is one of the better laboratory methods for evaluating the nutritive quality of forages (Barnes, 1967; Oh, Baumgardt and Scholl, 1966; Van Soest, Wine and Moore, 1966). Copyright © 1970. American Society of Animal Science . Copyright 1970 by American Society of Animal Science