'American Society of Agricultural and Biological Engineers (ASABE)'
Abstract
We have constructed a near-infrared (NIR) spectroscopic sensing system on an experimental basis. The NIR system can be used for on-line real-time monitoring of milk quality items such as fat, protein, lactose, somatic cell count, and milk urea nitrogen during milking with sufficient precision and accuracy. However, when the calibration models developed from a dataset were validated using a different data set, the performance of the calibration models was poor except for fat content. It seemed that various factors such as cow individuality, lactation stage and calving time caused the poor performance. However, it was not know which factor affected milk spectra and which wavelength range of the spectra was affected by the factors. We therefore analyzed milk spectra by principal component analysis in order to determine the reasons for poor performance. It was found that milk spectra were greatly affected by fat content and calving time. Calving time had a particularly great effect on the spectra in the wavelength range of 860 to 880 nm. In summary, using principal component analysis, we found the factor most affecting milk spectra and the wavelength of the spectra affected by the factor.Written for presentation at the 2006 ASABE Annual International Meeting Sponsored by ASAB
