Application of near infrared reflectance spectroscopy to forage analysis and prediction of TDN contents
1997
Amari, M. (National Inst. of Animal Industry, Kukizaki, Ibaraki (Japan)) | Abe, A.
Near infrared reflectance spectroscopy (NIRS) method was used to predict the chemical composition and total digestible nutrients (TDN) content of forage. A total of 388 out of 503 samples were used to develop the calibration equation. The samples consisted of temperate grass in the form of hay (n=126), silage (n=120), and its hay-silage mixture (n=60), and corn silage (n=142). The remaining 115 forages samples including temperature grass hay (n=58), silage (n=39), and corn silage (n=18) were used to validate the developed calibration equations. These samples were analyzed in duplicate for moisture, crude protein (CP) and crude fiber (CF) contents by the proximate method. Organic cellular contents (OCC), organic cell wall (OCW), low digestible fiber fraction (organic b fraction: Ob), and high digestible fiber fraction (organic a fraction: Oa) were determined by an enzymatic method, while acid detergent fiber (ADF) was determined by a detergent method. Accuracy of the predictions was assessed by the correlation coefficients (r) and standard error of prediction (SEP). Two prediction methods of the TDN by NIRS were compared. In the first method, NIRS values were extrapolated to the TDN value calculated by the following equations: (1) equation in Adams method, (2) equation in Martin method, (3) Donker equations, (4) equations based on enzymatic analysis, and (5) equation for detergent method. In the other method, the in vivo TDN was directly calibrated (direct method)
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