Alkali Requirements for Improving Digestibility of Hardwoods by Rumen Micro-Organisms

Abstract

The in vitro rumen digestibility of hardwoods increases following treatment with dilute NaOH for 1 to 4 hr. followed by washing. The response, however, varies inversely with lignin content of the treated materials. Digestibility rises to a maximum value with increasing ratio of alkali-to-wood. The minimum ratio at the maximum digestibility appears to be independent of species and is 5 to 6 g NaOH per 100 g of wood or about 100 lb/ton. The maximum digestibility with aspen is about 50%; with red oak, about 15%. This optimum ratio of NaOH to wood is in good agreement with the value calculated on the assumption that the only function of the alkali is to saponify ester linkages, thereby permitting additional swelling in water. Sodium hydroxide is inexpensive, and treating conditions are mild (room temperature, 1% NaOH solution). It is possible that washing of the treated wood is unnecessary or, at most, slight neutralization by weak acid may be required. Copyright © 1970. American Society of Animal Science . Copyright 1970 by American Society of Animal Science