Chemical Assays for Fiber, Lignin, and Lignin Components: Interrelationships and Near Infrared Reflectance Spectroscopic Analysis Results

Abstract

The objective of this study was to examine the variations in near infrared reflectance spectroscopic analysis when it is used for the analysis of fiber or lignin as determined by various chemical procedures. Second, the relationships between the various assay procedures were examined. Six fiber analyses (neutral detergent with and without sodium sulfite; acid detergent; ammonium oxalate; hot water-organic solvent extracted; and cellulase extracted), seven lignin analyses (permanganate; 72% sulfuric acid; sodium chlorite oxidation of acid detergent and two ammonium oxalate fibers; and acetyl bromide extraction on acid detergent and hot water-organic solvent-extracted fibers) and nitrobenzene oxidation (lignin composition determination) were studied. Assays were performed on 67 samples of five forages (alfalfa, tall fescue, orchardgrass, and the vegetative parts of corn and wheat plants) collected over the 1982 growing season. Near infrared reflectance spectroscopic analysis of ground feedstuffs (1-mm screen) showed that all chemical measures of fiber were equally and accurately assayed. Also, acetyl bromide lignin determined on ADF was assayed more accurately than the other lignin assays, and lignins determined on ammonium oxalate fiber were clearly not satisfactory. Regression analysis showed only the fiber analyses to be highly correlated with one another. © 1988, American Dairy Science Association. All rights reserved.