Santander Daniel, Clariget Juan, Banchero Georgget, Alecrim Fabiano, Simon Zinno Claudia, Mariotta Julieta, Gere José, Ciganda Verónica S
Instituto Nacional de Investigación Agropecuaria, Estación Experimental La Estanzuela, Ruta 50 km 11, Semillero, Colonia 70006, Uruguay.
Departamento de Geoquímica, Universidade Federal Fluminense, Outeiro São João Baptista s/n, Niterói 24020-141, Brazil.
Animals (Basel). 2023 Mar 28;13(7):1177. doi: 10.3390/ani13071177.
Understanding the methane (CH) emissions that are produced by enteric fermentation is one of the main problems to be solved for livestock, due to their GHG effects. These emissions are affected by the quantity and quality of their diets, thus, it is key to accurately define the intake and fiber content (NDF) of these forage diets. On the other hand, different emission prediction equations have been developed; however, there are scarce and uncertain results regarding their evaluation of the emissions that have been observed in forage diets. Therefore, the objectives of this study were to evaluate the effect of the NDF content of a forage diet on CH enteric emissions, and to evaluate the ability of models to predict the emissions from the animals that are consuming these forage diets. In total, thirty-six Angus steers (x¯ = 437 kg live weight) aged 18 months, blocked by live weight and placed in three automated feeding pens, were used to measure the enteric CH. The animals were randomly assigned to two forage diets (n = 18), with moderate (<50%, MF) and high (>50%, HF) NDF contents. Their dry matter intake was recorded individually, and the CH emissions were measured using the SF tracer gas technique. For the model evaluation, six prediction equations were compared with 29 studies ( = 97 observations), analyzing the accuracy and precision of their estimates. The emission intensities per unit of DMI, per ADG, and per gross energy intake were significantly lower ( < 0.05) in the animals consuming the MF diet than in the animals consuming the HF diet (21.7 vs. 23.7 g CH/kg DMI, 342 vs. 660 g CH/kg ADG, and 6.7% vs. 7.5%, respectively), but there were no differences in the absolute emissions ( > 0.05). The best performing model was the IPCC 2006 model ( = 0.7, RMSE = 74.04). These results show that reducing the NDF content of a forage diet by at least 10% (52 g/kg DM) reduces the intensity of the g CH/kg DMI by up to 8%, and that of the g CH/kg ADG by almost half. The use of the IPCC 2006 model is suitable for estimating the CH emissions from animals consuming forage-based diets.
由于肠道发酵产生的甲烷（CH₄）排放具有温室气体效应，因此了解这些排放是畜牧业需要解决的主要问题之一。这些排放受到日粮数量和质量的影响，因此准确确定这些草料日粮的摄入量和纤维含量（中性洗涤纤维，NDF）至关重要。另一方面，已经开发了不同的排放预测方程；然而，关于它们对草料日粮中观察到的排放的评估结果很少且不确定。因此，本研究的目的是评估草料日粮中NDF含量对肠道CH₄排放的影响，并评估模型预测食用这些草料日粮的动物排放的能力。总共使用了36头18月龄的安格斯阉牛（平均体重x¯ = 437 kg），按体重进行分组并安置在三个自动饲喂栏中，以测量肠道CH₄排放。将动物随机分配到两种草料日粮（n = 18）中，其NDF含量分别为中等（<50%，MF）和高（>50%，HF）。分别记录它们的干物质摄入量，并使用SF示踪气体技术测量CH₄排放。为了进行模型评估，将六个预测方程与29项研究（n = 97次观测）进行了比较，分析了它们估计值的准确性和精确性。采食MF日粮的动物每单位干物质摄入量、每单位平均日增重和每单位总能摄入量的排放强度显著低于（P < 0.05）采食HF日粮的动物（分别为21.7 vs. 23.7 g CH₄/kg DMI、342 vs. 660 g CH₄/kg ADG和6.7% vs. 7.5%），但绝对排放量没有差异（P > 0.05）。表现最佳的模型是IPCC 2006模型（R² = 0.7，RMSE = 74.04）。这些结果表明，将草料日粮的NDF含量降低至少10%（52 g/kg DM）可使CH₄/kg DMI的排放强度降低多达8%，使CH₄/kg ADG的排放强度降低近一半。使用IPCC 2006模型适合估算食用草料日粮的动物的CH₄排放量。
