McGinn S M, Beauchemin K A, Flesch T K, Coates T
Research Centre, Agriculture and Agri-Food Canada, Box 3000, Lethbridge, AB, Canada T1J 4B1.
J Environ Qual. 2009 Jul 23;38(5):1796-802. doi: 10.2134/jeq2008.0531. Print 2009 Sep-Oct.
Accurate measurements of enteric methane (CH(4)) emissions from cattle (Bos taurus) are necessary to improve emission coefficients used in national emissions inventories, and to evaluate mitigation strategies. Our study was conducted to evaluate a novel approach that allowed near continuous CH(4) measurement from beef cattle confined in pens. The backward Lagrangian Stochastic (bLS) dispersion technique was used in conjunction with global position system (GPS) information from individual animals, to evaluate CH(4) emissions from pens of cattle. The dispersion technique was compared to estimates of CH(4) production using the SF(6) tracer technique. Sixty growing beef cattle were fed a diet containing 60% barley silage (dry matter basis) supplemented with either barley (Hordeum vulgare L.) grain or corn (Zea mays L.) distillers dried grains. The results show that daily CH(4) emissions were about 7% lower for the dispersion technique than for the tracer technique (185 vs. 199 g CH(4) animal(-1) d(-1)). The precision of the dispersion technique, relative to the SF(6) tracer technique, expressed by the Pearson coefficient was 0.76; the relative accuracy given by the concordance coefficient was 0.69. The bLS dispersion technique was able to detect differences (P < 0.05) due to diet and has the added advantage of measuring the pattern of CH(4) production during the 24-h period, with emissions ranging from 161 to 279 g CH(4) animal(-1) d(-1). Configuring the cattle as point sources resulted in more accurate CH(4) emissions than assuming a uniform area release from the pen surface. The results indicate that the bLS dispersion technique using cattle as point sources can be used to accurately measure enteric CH(4) from cattle and to evaluate the impact of dietary mitigation strategies.
准确测量牛（Bos taurus）的肠道甲烷（CH₄）排放量对于改进国家排放清单中使用的排放系数以及评估减排策略至关重要。我们开展这项研究是为了评估一种新方法，该方法能够对圈养在围栏中的肉牛进行近乎连续的CH₄测量。反向拉格朗日随机（bLS）扩散技术与来自个体动物的全球定位系统（GPS）信息相结合，用于评估牛围栏的CH₄排放量。将该扩散技术与使用SF₆示踪技术估算的CH₄产量进行了比较。六十头生长中的肉牛被喂食含有60%大麦青贮料（干物质基础）的日粮，并补充大麦（Hordeum vulgare L.）谷物或玉米（Zea mays L.）干酒糟。结果表明，扩散技术的每日CH₄排放量比示踪技术低约7%（185对199 g CH₄/动物⁻¹·d⁻¹）。相对于SF₆示踪技术，扩散技术的精度由皮尔逊系数表示为0.76；一致性系数给出的相对准确度为0.69。bLS扩散技术能够检测到由于日粮导致的差异（P < 0.05），并且具有测量24小时期间CH₄产生模式的额外优势，排放量范围为161至279 g CH₄/动物⁻¹·d⁻¹。将牛配置为点源比假设从围栏表面均匀释放面积能得出更准确的CH₄排放量。结果表明，将牛作为点源的bLS扩散技术可用于准确测量牛的肠道CH₄，并评估日粮减排策略的影响。
