Prediction of Feed Digestibility Using Differences in NIRS Spectra between Feeds and Feces at a Determined Region of Wavelength

Abstract

Abstract A total of seventy-two pairs of feed and fecal samples collected from the digestion trials of dairy catlle were used in the study to predict dry matter digestibility (OMO). organic matter digestibility (OMO) and total digestible nutrients (TON) using near infrared reflectance spectroscopy. Calibration and prediction were made from the difference of second derivative spectra between feeds and feces. From these spectra. 31. 28 and 13 samples were separated for calibration. prediction and test. respectively. Wavelengths of 1878.2172.2278 and 2362nm were selected from determined region at 1900-.2200-.2300-and 2400-nm for developing the calibration equations for DI\10. OMO and TDN. Correlation coefficient for DMD. OMD and TDN of the calibration were 0.95, 0.92 and 0.95, respectively. while the standard error were 2.9 for the first two nutrients and 2.8 for TDN. Whereas, r values (and standard error) for the prediction equations were 0.89 (3.5). 0.92 (3.32), and 0.91 (3.16), while for the test samples, were 0.97 (1.96). 0.97 (1.88) and 0.96 (1.94). respectively. This study showed the possibility and applicability of predicting digestibil· ity and TDN using the spectra difference of feeds and feces through the wavelengths from four determined regions above 1900-nm. Anim. Sci. Technol. (Jpn.) 69 (3) : 253-259. 1998 Key words: NIRS. Digestibility. Dairy cattle