HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Van Soest, P. J. Search for Related Content PubMed Articles by Van Soest, P. J.

Development of a Comprehensive System of Feed Analyses and its Application to Forages¹

United States Department of Agriculture²

Abstract

Forage dry matter can be divided into two fractions on the basis of nutritional availability. The first fraction corresponds to the cellular contents and is composed of lipids, soluble carbohydrates, most protein and other water-soluble matter. This fraction is essentially available, but its digestibility appears incomplete because of the excretion of fecal non-cell-wall matter, which is principally of endogenous and bacterial origin.

The second fraction corresponds to the plant cell wall, the availability of which is controlled by structural features that link cellulose, hemicellulose and lignin together. Of the cell-wall components, hemicellulose is a large and variable fraction which prevents crude fiber, cellulose, or lignin from being a good estimator of the content of the plant cell wall. The plant cell wall corresponds to what can be nutritionally denned as a total fiber fraction. The nutritive availability of the cell-wall fraction is not uniform among forages.

The dual nutritive character of plant dry matter contraindicates the use of single factors to predict whole dry-matter digestibility.

¹ Invited paper presented at the 58 th Annual Meeting of the American Society of Animal Science, New Brunswick, New Jersey.

² Animal Husbandry Research Division, ARS, Beltsville, Maryland.

This article has been cited by other articles:

				G. I. Zanton and A. J. Heinrichs Analysis of Nitrogen Utilization and Excretion in Growing Dairy Cattle J Dairy Sci, April 1, 2008; 91(4): 1519 - 1533. [Abstract] [Full Text] [PDF]

				I. K. Hindrichsen, M. Kreuzer, J. Madsen, and K. E. B. Knudsen Fiber and lignin analysis in concentrate, forage, and feces: detergent versus enzymatic-chemical method. J Dairy Sci, June 1, 2006; 89(6): 2168 - 2176. [Abstract] [Full Text] [PDF]

				G. Ferreira and D. R. Mertens Chemical and Physical Characteristics of Corn Silages and Their Effects on In Vitro Disappearance J Dairy Sci, December 1, 2005; 88(12): 4414 - 4425. [Abstract] [Full Text] [PDF]

				D. R. Mertens Challenges in measuring insoluble dietary fiber J Anim Sci, December 1, 2003; 81(12): 3233 - 3249. [Abstract] [Full Text] [PDF]

				A. J. Moeser, I. B. Kim, E. van Heugten, and T. A. T. G. Kempen The nutritional value of degermed, dehulled corn for pigs and its impact on the gastrointestinal tract and nutrient excretion J Anim Sci, October 1, 2002; 80(10): 2629 - 2638. [Abstract] [Full Text] [PDF]

				W. Karasov and J. Diamond Digestive adaptations for fueling the cost of endothermy Science, April 12, 1985; 228(4696): 202 - 204. [Abstract] [PDF]