The objectives of this study were to investigate the relationship between the in vitro ruminal ammonia nitrogen (NH₃-N) concentration and the Cornell Net Carbohydrate and Protein System (CNCPS) N-fractions of feeds for cattle and further compare the performance of developing multiple linear regression (MLR) and artificial neural network (ANN) models in estimating the NH₃-N concentration in rumen fermentation. Two data sets were established, of which the training data set containing forty-five rations for cattle with concentrate/roughage ratios of 50:50, 40:60, 30:70, 20:80 and 10:90 used for developing models and the test data set containing ten other rations with the same concentrate/roughage ratios with the training data set were used for validating of models. The NH₃-N concentrations of feed samples were measured using an in vitro incubation technique. The CNCPS N-fractions (g), for example PB₁ (rapidly degraded true protein), PB₂ (neutral detergent soluble nitrogen), PB₃ (acid detergent soluble nitrogen) of rations, were calculated based on chemical analysis. Statistical analysis indicated that the NH₃-N concentration (mg) was significantly correlated with the CNCPS N-fractions (g) PB₁, PB₂ and PB₃ in a multiple linear pattern: NH₃-N = (130.70±33.80) PB₁ + (155.83±17.89) PB₂ - (85.44±37.69) PB₃ + (42.43±1.05), R² = 0.77, p < 0.0001, n = 45. The results indicated that both MLR and ANN models were suitable for predicting in vitro NH₃-N concentration of rations using CNCPS N-fractions PB₁, PB₂, and PB₃ as independent variables while the neural network model showed better performance in terms of greater r², CCC and lower RMSPE between the observed and predicted values.

中文翻译：

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基于低精粗比牛日​​粮 CNCPS 含氮部分的多重线性模型和人工神经网络估计体外瘤胃氨氮

本研究的目的是研究牛饲料的体外瘤胃氨氮 (NH ₃ -N) 浓度与康奈尔净碳水化合物和蛋白质系统 (CNCPS) N 分数之间的关系，并进一步比较开发多种饲料的性能。估计 NH ₃的线性回归 (MLR) 和人工神经网络 (ANN) 模型-N 在瘤胃发酵中的浓度。建立了两个数据集，其中训练数据集包含 45 份精粗比为 50:50、40:60、30:70、20:80 和 10:90 的牛日粮，用于开发模型和测试数据集包含与训练数据集相同的精/粗比率的十个其他口粮，用于验证模型。使用体外培养技术测量饲料样品的NH _{3 -N浓度。}CNCPS N-分数 (g)，例如 PB ₁ (快速降解的真蛋白)、PB ₂ (中性去污剂可溶性氮)、PB ₃(酸性洗涤剂可溶性氮)的口粮，根据化学分析计算。统计分析表明NH ₃ -N浓度(mg)与CNCPS N-分数(g) PB ₁、PB ₂和PB ₃呈多重线性关系：NH ₃ -N = (130.70±33.80) PB ₁  + (155.83±17.89) PB ₂ - (85.44±37.69) PB ₃  + (42.43±1.05), R ²  = 0.77, p  < 0.0001, n = 45。结果表明MLR和ANN模型都适用于预测体外NH ₃-N 日粮浓度使用 CNCPS N 分数 PB ₁、PB ₂和 PB ₃作为自变量，而神经网络模型在观察值和预测值之间的更大r ²、CCC 和更低 RMSPE 方面表现出更好的性能。