Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2000
Publication Date: N/A
Technical Abstract: Near Infrared Reflectance Spectroscopy (NIRS) a rapid, nondestructive method of analysis requiring minimal sample preparation was first used to predict nutritive value of forage crops in 1976. NIRS has been approved by AOAC for moisture, Kjeldahl nitrogen, and acid detergent fiber (ADF). Commercial forage testing laboratories have used NIRS for routine analysis of hay, haylage, corn silage, and corn grain for moisture, CP, ADF, NDF, Ca, P, K, and Mg. The accuracy of NIRS is dependent upon a calibration developed from samples representing the population to be predicted with accurately determined conventional analytical methods. The success depends on the specificity and concentration of the analyte, precision of the conventional method of analysis, and the degree to which samples chosen for calibration represent those to be predicted. Properly calibrated NIRS instruments rapidly make several determinations simultaneously. The chief disadvantages include the need for expensive, high-precision spectroscopic instruments; dependence on laborious and often in exact laboratory determinations for monitoring the procedure; and lack of sensitivity to minor constituents. Advances in instrument performance have increased spectral accuracy and output consistency between instruments. Software advances have improved data extraction from spectra, operator understanding of the limitations of calibration equations, and ability of network managers to monitor analytical output of instruments from remote locations. NIRS Forage and Feed Testing laboratories produced NIRS average hay analyses for CP, ADF, and aNDF within 4.2, 2.1, and 5.0 g/kg units of the RMA, respectively.