Walker J W, Campbell E S, Lupton C J, Taylor C A, Waldron D F, Landau S Y
Texas Agricultural Experiment Station, Texas A&M University Agricultural Research and Extension Center, N. San Angelo, Texas 76901, USA.
J Anim Sci. 2007 Feb;85(2):518-26. doi: 10.2527/jas.2006-202.
The effects of breed, sex, and age of goats on fecal near-infrared reflectance spectroscopy-predicted percentage juniper in the diet were investigated, as were spectral differences in feces from goats differing in estimated genetic merit for juniper consumption. Eleven goats from each breed, sex, and age combination, representing 2 breeds (Angora and meat-type), 3 sex classifications (female, intact male, and castrated male), and 2 age categories [adult and kid (less than 12 mo of age)] were fed complete, pelleted rations containing 0 or 14% juniper. After 7 d on the same diet, fecal samples were collected for 3 d, and the spectra from the 3 replicate samples were averaged. Fecal samples were assigned to calibration or validation data sets. In a second experiment, Angora and meat goats with high or low estimated genetic merit for juniper consumption were fed the same diet to determine the effect of consumer group on fecal spectra. Feces were scanned in the 1,100- to 2,500-nm range with a scanning reflectance monochromator. Fecal spectra were analyzed for the difference in spectral characteristics and for differences in predicted juniper in the diet using internal and independent calibration equations. Internal calibration had a high precision (R(2) = 0.94), but the precision of independent validations (r(2) = 0.56) was low. Spectral differences were affected by diet, sex, breed, and age (P < 0.04). However, diet was the largest source of variation in spectral differences. Predicted percentage of juniper in the diet also showed that diet was the largest source of variation, accounting for 95% of the variation in predictions from internal calibrations and 51% of the variation in independent validations. Predictions from independent calibrations readily detected differences (P < 0.001) in the percentage of juniper in the 2 diets, and the predicted differences were similar to the actual differences. Predicted juniper in the diet was also affected by sex. Feces from goats from different juniper consumer groups fed a common diet were spectrally different, and the difference may have resulted from a greater intake by high- compared with low-juniper-consuming goats. Fecal near-infrared reflectance spectroscopy predictions of botanical composition of diets should be considered an interval scale of measurement.
研究了山羊的品种、性别和年龄对粪便近红外反射光谱预测日粮中杜松百分比的影响，以及不同杜松摄入量估计遗传价值的山羊粪便的光谱差异。从每个品种、性别和年龄组合中选取11只山羊，代表2个品种（安哥拉山羊和肉用型山羊）、3种性别分类（雌性、未阉割雄性和阉割雄性）以及2个年龄类别[成年羊和羔羊（小于12月龄）]，分别饲喂含0%或14%杜松的全价颗粒日粮。在相同日粮饲喂7 d后，连续3 d采集粪便样本，并将3个重复样本的光谱进行平均。粪便样本被分配到校准或验证数据集。在第二个实验中，对杜松摄入量估计遗传价值高或低的安哥拉山羊和肉用山羊饲喂相同日粮，以确定消费群体对粪便光谱的影响。使用扫描反射单色仪在1100至2500 nm范围内扫描粪便。利用内部和独立校准方程分析粪便光谱的光谱特征差异以及日粮中预测杜松的差异。内部校准具有较高的精度（R(2)=0.94），但独立验证的精度（r(2)=0.56）较低。光谱差异受日粮、性别、品种和年龄的影响（P<0.04）。然而，日粮是光谱差异最大的变异来源。日粮中杜松的预测百分比也表明，日粮是最大的变异来源，占内部校准预测变异的95%和独立验证变异的51%。独立校准的预测能够轻松检测出两种日粮中杜松百分比的差异（P<0.001），且预测差异与实际差异相似。日粮中预测的杜松也受性别的影响。饲喂相同日粮的不同杜松消费群体的山羊粪便在光谱上存在差异，这种差异可能是由于杜松摄入量高的山羊比摄入量低的山羊摄入量更大所致。应将粪便近红外反射光谱对日粮植物成分的预测视为一种区间测量尺度。
