Near Infrared Spectroscopic Analysis of Lignin Components in Sodium Chlorite-Treated and Untreated Forages and Forage By-Products

Abstract

Lignin composition by near infrared reflectance spectroscopy was determined in alfalfa, tall fescue, and orchardgrass hays and the vegetative parts of corn and wheat plants collected over the 1982 growing season at Beltsville, MD and in 16 feeds treated with NaClO3. The objective was to determine how well near infrared reflectance spectroscopy performed in determining lignin composition and to see if equations developed for one set of feeds were applicable to another. Six hays, two straws, four stovers, three hulls, and corn cobs were treated with NaClO3 at eight rates to give 0 to .394 g of NaClO3/g of feedstuff. Comparison of the chemically determined lignin composition with that determined by near infrared reflectance spectroscopy showed that 1) more accurate determinations were obtained when samples from all treatment rates were included in the calibration set, 2) results with the untreated 1982 samples were more accurate than for the treated samples, 3) determining lignin composition of the treated samples with equations developed for the untreated 1982 samples (or the reverse) did not work, and 4) results achieved with near infrared reflectance were comparable to those obtained by chemical assay. Although the same constituents were determined chemically for both sets of feeds, this lack of cross predictability, like the poor results for the treated feeds, may be due to interference by products produced by the NaClO3 treatment.