Niero Giovanni, Cendron Filippo, Penasa Mauro, De Marchi Massimo, Cozzi Giulio, Cassandro Martino
Department of Agronomy, Food, Natural resources, Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro (PD), Italy.
Department of Animal Medicine, Production and Health, University of Padova, Viale dell'Università 16, 35020 Legnaro (PD), Italy.
Animals (Basel). 2020 Apr 1;10(4):606. doi: 10.3390/ani10040606.
Methane (CH) emissions represent a worldwide problem due to their direct involvement in atmospheric warming and climate change. Ruminants are among the major players in the global scenario of CH emissions, and CH emissions are a problem for feed efficiency since enteric CH is eructed to the detriment of milk and meat production. The collection of CH phenotypes at the population level is still hampered by costly and time-demanding techniques. In the present study, a laser methane detector was used to assess repeatability and reproducibility of CH phenotypes, including mean and aggregate of CH records, slope of the linear equation modelling the aggregate function, and mean and number of CH peak records. Five repeated measurements were performed in a commercial farm on three Simmental heifers, and the same protocol was repeated over a period of three days. Methane emission phenotypes expressed as parts per million per linear meter (ppm × m) were not normally distributed and, thus, they were log-transformed to reach normality. Repeatability and reproducibility were calculated as the relative standard deviation of five measurements within the same day and 15 measurements across three days, respectively. All phenotypes showed higher repeatability and reproducibility for log-transformed data compared with data expressed as ppm × m. The linear equation modelling the aggregate function highlighted a very high coefficient of determination (≥0.99), which suggests that daily CH emissions might be derived using this approach. The number of CH peaks resulted as particularly diverse across animals and therefore it is a potential candidate to discriminate between high and low emitting animals. Results of this study suggest that laser methane detector is a promising tool to measure bovine CH emissions in field conditions.
甲烷（CH₄）排放因其直接参与大气变暖及气候变化而成为一个全球性问题。反刍动物是全球CH₄排放场景中的主要排放源之一，并且CH₄排放对饲料效率而言是个问题，因为瘤胃CH₄排放会对牛奶和肉类生产造成损害。在群体水平上收集CH₄表型仍受到成本高昂且耗时的技术的阻碍。在本研究中，使用激光甲烷探测器来评估CH₄表型的重复性和再现性，包括CH₄记录的均值和总和、模拟总和函数的线性方程的斜率，以及CH₄峰值记录的均值和数量。在一个商业农场对三头西门塔尔小母牛进行了五次重复测量，并在三天的时间段内重复相同的方案。以每线性米百万分率（ppm×m）表示的甲烷排放表型呈非正态分布，因此，对其进行对数转换以达到正态分布。重复性和再现性分别计算为同一天内五次测量以及三天内十五次测量的相对标准偏差。与以ppm×m表示的数据相比，所有表型的对数转换数据均显示出更高的重复性和再现性。模拟总和函数的线性方程突出显示了非常高的决定系数（≥0.99），这表明可以使用这种方法得出每日CH₄排放量。CH₄峰值数量在不同动物之间差异特别大，因此它是区分高排放和低排放动物的潜在候选指标。本研究结果表明，激光甲烷探测器是在现场条件下测量牛CH₄排放的一种有前景的工具。
