Document Type

Thesis - Open Access

Award Date

1986

Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Robbi Pritchard

Abstract

Cellulose is the most abundant and insoluble polysaccharide of the cell wall constituents. It is a polymer of glucose units in which the degree cellulose of polymerization varies within and between sources of. Availability to the rumen microflora ranges from 25 to 90%, making it a potential source of energy for ruminants. Hemicellulose consists of short chains of glucan, polymers of xylose, mannose and galactose plus a mixture of sugars and uronic acid polymers. Lignin is an aromatic compound that is indigestible and is of no nutritive value to mammals. Its main function is to supply strength and rigidity to the plant material. The nutritional significance effects of lignin lies in its indigestible nature and subsequent acting as a physical barrier impeding the microbial breakdown of hemicellulose and cellulose. Williams et al. indicated that the high level of lignocellulosic components in wood and wood by-products is also associated with relatively low levels of potassium, calcium and some trace minerals that may limit microbial fermentation. The association between lignin and the other major fiber constituents appears to limit bacterial and enzymatic access to the carbohydrates of the cell wall, leaving wood and wood residues essentially unavailable to ruminants. Pidgen and Heaney and Van Soest have concluded that the chemical composition of lignocellulose and maturity of the availability in the rumen depend on the stage of plants and the digestibility of the hemicellulose component. There is a decrease in cell content as plants mature due to increased lignification which encrusts and protects the cell wall from bacterial attack. In later stages of maturity, xylan and uronic acid which are the major components of hemicellulose are highly indigestible. The different sources cited in this review showed that wood residues such as wood pulp and sawdust, treated by alkali or acid hydrolysis can effectively be used as ruminant feed supplement. Chemical treatment enhances the digestibility of cell wall content and decreases lignin content of these products. The substitution of these roughages for a given quantity of concentrates in ruminant diet did not induce toxicity effect and did not affect animal performance.

Library of Congress Subject Headings

Ruminants -- Feeding and feeds
Wood waste -- By-products

Format

application/pdf

Number of Pages

46

Publisher

South Dakota State University

Rights

No Copyright - United State
http://rightsstatements.org/vocab/NoC-US/1.0/

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