Author
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Clapham, William |
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Foster, Joyce |
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Fedders, James |
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Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 7/22/2003 Publication Date: 11/2/2003 Citation: Clapham, W.M., Foster, J.G., Fedders, J.M. 2003. Use of near-infrared reflectance spectroscopy to determine fatty acid content of forages. American Society of Agronomy Abstracts. Paper No. C03-Clapham-835013. Interpretive Summary: Technical Abstract: Utilization of near-infrared reflectance spectroscopy (NIR) to determine fatty acid concentration of forages could result in more rapid sample analysis at a lower cost than traditional wet-chemistry techniques. Our objective is to determine the feasibility of using NIR to assess fatty acid concentrations in forages. A greenhouse experiment was conducted in the winter of 2002 to generate forage samples from 13 species/varieties of grasses, legumes and forbs at three stages of growth. Samples were freeze-dried, ground and analyzed by wet-chemistry and NIR techniques. One-half of the 195 samples were used to develop an NIR calibration file for each of ten fatty acids with the remaining half used as a validation data set. Fatty acids with concentrations averaging less than 200 ug/g on a dry matter basis (C12:0, C14:0, C14:1, C16:1 and C20:0) produced calibrations with 1-VR values of less than 0.50 and appear unsuitable for accurate assessment via NIR. The C16:0, C18:0, C18:1, C18:2 and C18:3 fatty acids had average concentrations greater than 700 ug/g and 1-VR values >0.78. Correlations between NIR and wet chemistry results for these most abundant fatty acids had r-values ranging from 0.72 to 0.90. These results suggest that NIR may be a suitable technique to assess the dominant fatty acids in forages. Work is continuing to further refine the NIR calibrations. |
