Author
 |
REEVES JAMES B - 1265-50-00 |
|
Submitted to: Near Infrared Spectroscopy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/10/1995 Publication Date: N/A Citation: N/A Interpretive Summary: The determination of the composition of animal feedstuffs has traditional been done by chemical analyses, which are time consuming and generate hazardous chemical wastes. More recently non-chemical procedures using light have been developed. One such procedure is called near infrared reflectance spectroscopy (NIRS). This procedure compares the values obtained chemically to the results obtained for the interaction of light with the sample in question. The results of these comparisons are then used to predict other samples. One central problem encountered is that the comparisons developed are very dependent on the samples used. Thus results for alfalfa grown in one location often can be used to determine the composition of alfalfa samples grown in another location. The objectives of this work were to explore the ability of NIRS using a different instrument (FTNIR), and the usefulness of a different kind of light (FTIR) to determine sample composition. Sixty seven samples consisting of 15 alfalfa, 16 tall fescue, and 15 orchardgrass hays, 10 corn stovers, and 11 wheat straws at various stage of maturity were examined. The results showed that FTIR can perform as well and sometimes better than NIRS in determining the composition of forages and by-products. In addition, FTNIR spectroscopy did not appear to be as useful as either the older NIR instrument or the FTIR. Further work with more diverse data sets and various FTIR configurations will be needed to further define the limits and usefulness of FTIR in the determination of feedstuff composition. Technical Abstract: The objectives of this work were to explore the question of the relative value of near and mid-infrared diffused reflectance spectroscopy in determining the composition of forages and by-products. Sixty seven samples consisting of 15 alfalfa, 16 tall fescue, and 15 orchardgrass hays, 10 corn stovers, and 11 wheat straws at various stage of maturity were examined by diffuse reflectance using a scanning monochromator (1100 to 2500 nm), an FTNIR (10,000 to 4,000 cm-1, 4 and 16 cm-1 resolution) and an FTIR (4,000 to 400 cm-1, 4 and 16 cm-1 resolution, with and without dilution with KBr) spectrometer. Samples were analyzed chemically and spectroscopically for fibers, in-vitro digestibility, nitrobenzene oxidation products and various measures of lignin content. The results showed that diffuse mid-infrared reflectance spectroscopy can perform as well and sometimes better than diffuse near infrared spectroscopy in determining the composition of forages and by-products. In addition, FTNIR spectroscopy does not appear to be as useful as either near infrared using a scanning monochromator or as an FTIR spectrometer. Finally, diluting samples with KBr was not found to be beneficial for either FTNIR or FTIR determinations. Further work with more diverse data sets and various FTIR configurations will be needed to further define the limits and usefulness of FTIR in the determination of lignocellulosic materials. |
