Predicting Total Digestible Nutrient Losses From Heat Damaged Hays and Haylages with NIR

摘要

During the storage of hay or haylage, heating damage may occur and lead to losses of available protein and digestible nutrients. Recent research indicates that losses of total digestible nutrients (TDN) may be more significant economically than lossesof available protein. Our objectives for this study were to establish a near-infrared reflectance spectroscopy (NIRS) model to estimate losses of TDN caused by heating damage during storage, to test the model on farmer samples obtained from commercial forage testing laboratories, and then to determine the frequency with which significant losses of TDN occurred within these producer samples. Hay/haylage samples from wrapped bales harvested with moisture ranges of 9.3 to 17.3%, 16.8 to 24.2%, and 26.7 to46.6% for three different harvests in a previous study in which internal bale temperatures were measured daily were utilized to develop a NIRS calibration. The model external validation coefficient of determination (R~2) was 0.88. The calibration was tested on three unknown sets of samples from commercial forage testing laboratories. The three sets contained spectra of 1000, 618, and 1994 forage samples submitted by producers. A very small number of samples in Sets 1, 2, and 3 exhibited H values > 3 (21, 11, and 66 samples, respectively), which indicates that the developed equation was appropriate for use on the commercial samples. The predicted TDN losses from producer samples due to heating exceeded 4 TDN units in 50% of the samples, and exceeded 8TDN units in 16% of the samples. Heat damage is a significant economic loss to many farmers.