Analysis of Forages by Infrared Reflectance

Abstract

Infrared reflectance is a rapid accurate procedure for measuring nutrients in grains and forages. Factors that affect prediction of forage quality include plant species, method of preservation, and constituents in the forage other than those being measured. Selection of wavelengths for prediction is the key. Statistical procedures are being studied to improve selection of wavelength and to lower prediction errors. Commercial instruments recently introduced have greater data processing capabilities and greater wavelength (filter) selection than earlier models, but more research is needed to determine the appropriate wavelengths for each type of forage and feedstuff. An alternative to the filter instrument would be a small monochromator-based instrument similar to the prototype we have developed. This instrument can collect, process, and select a set of wavelengths to use for prediction for each different wpe of forage or feedstuff. New applications of infrared reflectance include identification of the sample from the spectra, prediction of percent legume +10% in grass-legume mixtures, heat damaged protein (acid detergent fiber insoluble nitrogen -+.01%), phosphorous -+.04%, calcium +.14%, calcium to phosphorous ratio +.68%, po-