Digestibility of Tanoak

Abstract

Tanoak is considered a weed species in northwestern California. Dry-matter and cellulose digestibility trials were made with sheep to determine the possibility of using ground waste tanoak as an energy source in livestock rations. In vitro dry-matter and cellulose digestibility values were consistently higher than the in vivo values. The in vitro dry-matter digestibility averaged 12.7% for four sheep, while the in vivo dry-matter digestibility averaged 8.9%. The in vitro cellulose digestibility averaged 5.0%; the in vivo cellulose digestibility averaged 1.0%. It was concluded that tanoak residues can only have consideration as an energy source to ruminants when some form of pretreatment can release the wood carbohydrates from their association with lignin.