Near-IR spectroscopy predictions can determine the digestibility and feed intake from feedlot lambs

ABSTRACT This research was carried out to validate the effectiveness of the Near-IR spectroscopy method in predicting intake and digestibility of DM and nutrients of diets for feedlot lambs, in order to compare with the conventional laboratory method. Samples of diets, ort,s and feces of forty Santa Ines lambs were subjected to both methods and analyzed for DM, MM, NDF, ADF, CP, and EE for future calculations for intake and digestibility. Most of the model's correlation coefficient was in the range of 0.66 to 0.81, being suitable for quantitative prediction. Highest values for CP content of 0.85 (diets) and 0.87 (orts) were observed. There were high correlations between the methods to predicting intake (average values of 0.93) and digestibility (average values of 0.93). Correlations between the variables obtained by the prediction of NIRS and the conventional method were adequate, showing that regardless of the method, the nutritional content of diets, orts and feces can be used to calculate the intake and digestibility of DM and nutrients of lambs’ diets. The Near-IR spectroscopy method is recommended for accuracy, speed and low cost compared to conventional method.

摘要：本研究旨在验证近红外光谱（Near-IR spectroscopy）法在预测育肥羔羊日粮干物质（DM）及营养物质采食量与消化率方面的有效性，并与常规实验室方法进行对比。研究采集了40只圣塔伊内斯（Santa Ines）羔羊的日粮、饲剩样本与粪便样本，采用两种方法开展检测，针对干物质（DM）、MM、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、粗蛋白（CP）及粗脂肪（EE）进行分析，用于后续采食量与消化率的计算。模型的多数相关系数介于0.66至0.81之间，适用于定量预测。其中粗蛋白（CP）含量的相关系数最高，日粮样本达0.85，饲剩样本达0.87。两种方法在预测采食量（平均相关系数为0.93）与消化率（平均相关系数为0.93）方面均呈现极高相关性。近红外光谱法所得预测变量与常规实验室方法的相关性均符合要求，结果表明，无论采用哪种方法，均可通过日粮、饲剩样本及粪便的营养成分计算羔羊日粮干物质与营养物质的采食量及消化率。相较于常规实验室方法，近红外光谱法凭借准确性高、检测速度快且成本低廉的优势，值得推广应用。