The authors would like to thank the staff of the Department of Animal Science&#8217;s Dairy Center for their conscientious care of the experimental cows used to generate data for this study.

参与了代表性的结果中描述的实验动物进行照顾根据宾夕法尼亚州立大学动物护理和使用委员会的指导方针。委员会审议并通过了试验，并在研究进行的所有手续。细节，例如动物和饮食组成信息和实验设计，可在全公布此实验12中找到。 注意:对于设备和进行实验， 参见材料表需要耗材的列表。 1.实验设计<ol><li>获得机构动物护理和使用委员会的批准实验。这是一种非侵入性的过程，不引起疼痛的动物，并归类为USDA C类（ 轻微或瞬间疼痛或痛苦或无疼痛或痛苦 ）。麻醉是没有必要的。 </li><li>选择完整（ 即非空心）牛基于泌乳阶段，年龄，和牛奶产量的实验。不使用空心奶牛瘤胃因为气体通过套管潜在泄漏的同AHCS。设计为缓解这一问题的装置，目前正在测试，但结果并不这里报告。 </li><li>如果交叉设计（即，拉丁方，例如）是利用，使用8至12头奶牛，这取决于治疗次数，在复制的设计为将残余效应均衡。如果，例如，4个处理进行测试，8奶牛将产生一个复制的4×4的设计试验， 等等 。这些类型的实验最小建议持续时间为21至28天，与第一14至21天的适应治疗和7天进行数据收集。 </li><li>如果一个随机区组设计是利用，使用12至15头奶牛每个处理。包括2周协变量周期的数据收集开始之前。这些实验的推荐的持续时间为8至12周时，与第2周贝因克适应治疗。 </li><li>装备各实验动物与ISO 11784或11785兼容的RFID识别标签。 </li></ol>动物2.培训使用AHCS <ol><li>在实验开始前，移动AHCS进入该设施所在的母牛的位置。将单元内的奶牛视力。将本机有至少2天。 </li><li>准备鱼饵饲料的动物一样。不同饲料可以试图吸引牛，虽然（原样重量计）已成功地在实验室中使用的70％磨碎的玉米，27％的干糖浆，和3％的大豆油的混合物。避免可能会堵塞空气过滤器和AHCS的进料输送系统粘和尘土飞扬的饲料。优选的是将进料沉淀。 </li><li>通过将其放置在它们被用于饲料，顶部为了让他们熟悉饵饲料给饲料所有动物的少量（少数）。 </li><li>非常缓慢地移动AHCS到约1.5 M FR嗡的动物。 </li><li>将约1公斤饵料喂成斗让动物香，味饵饲料。渐渐地将水桶朝AHCS单位的料桶，迫使动物伸展和对AHCS料桶达到。 </li><li>转储一些从桶里饵饲料进入AHCS饲槽和缓慢移动AHCS单位对牛。如果在任何时候的训练，牛变成忧虑或恐惧，移动设备远离她，然后再试一次，在另一个时间或日期。 </li><li>在数天的过程中，重复训练直到动物习惯于并且由AHCS单元，（即诱饵饲料）激发。如果动物不能习惯AHCS，替换另一种动物实验开始前和培养遵循上面的程序的新的动物。 </li></ol> 3.校准AHCS的注:CO 2的传感器的浓度范围为0至5％;该范围为CH 4的传感器是0〜2％。检测下限是20 ppm的CH 4和50ppm的CO 2。没有关于甲烷和CO 2的高背景水平的担忧，因为检测限远比在动物设施这些气体的安全高背景水平更大。 <ol><li>为最大的精确度，在每一个气体测量实验结束时执行该校准过程5次在开始时和3次。 </li><li>使用下面的气体（ 见材料表 ）:跨度气体和100％N 2（纯度为99.999％）0.15％CH 4和1％ 的 CO 2（级认证的大师班，精度±2％），零气。 </li><li>填补的样品袋用2L零气体，而另一个袋用2L跨度气体混合物。一定要使用完全瘪袋。填写校准的一天，新的天然气袋。 </li><li> 1年的使用或更少，如果有必要的后更换袋。 </li><li>冒气标准，以其中气体测定实验发生的场所。如果动物与测量发生在一个封闭的工厂（ 即 ，乳品谷仓），在整个校准过程ON打开谷仓的球迷。这是必要的，以减少甲烷浓度在后台空气的效果。 </li><li>打开AHCS开，让校准至少30分钟才温暖。除去从位于前面板内刻度管止挡。确保有处于校准管没有水。除去水，如果需要的话。水会破坏气体浓度传感器。 </li><li>连接N 2袋样品（零气体）校准管。拧下样品袋逆时针1整圈的胶阀允许流动。 </li><li>打开"运行校准"旋钮位于AHCS的仪表控制面板"校准"上。这将开始抽的样品从袋子。一旦流程开始，按按住"校准"按钮约10秒钟，然后松开。 </li><li>等待样品袋放气至约10％其容量的。不要完全清空包包，它可能会损坏传感器。一旦袋约10％的产能，打开"运行校准"按钮返回到"RUN"。 </li><li>关闭样品袋并从刻度管断开。等待2分钟，然后，跨度气体混合物袋连接到刻度管。 </li><li>重复步骤3.7。 </li><li>一旦流程开始后，按住"校准"按钮3秒，然后松开。 </li><li>重复步骤3.10。 </li><li>关闭样品袋并从刻度管断开。更换瓶塞到刻度管。 注:校准完成后，"因子"值将出现在Web页面上的数据卡。的因素变化系数应小于3％，为甲烷和二氧化碳2，R 1％espectively。如果不在该范围内，则重复校准。 </li></ol> 4. CO 2恢复测试<ol><li>在每台气体测量试验前的CO 2回收率试验至少一次（3版本= 1缸CO 2）。在连续应用中，每月进行一次恢复测试。 </li><li>确保CO 2的回收率测试阀关闭（阀是垂直于出口喷嘴）。安装一个新的CO 2缸的发布制度，并打开阀门顺时针，直到紧。 </li><li>能级，零的大规模。将整个释放系统的规模，以确保它是正确的。测试，以确保CO 2的流动:打开开/关阀，并迅速再次关闭它一边听的CO 2离开喷嘴。应当CO 2被流过"whishing"的声音。 </li><li> 二氧化碳钢瓶固定架安装到料桶。从n个流量上，不要让动物们靠近/呼吸进纸器中。人们也不能呼吸放入进纸器。 </li><li>权衡的 CO 2气缸与释放系统。记录这个质量为初始质量。记录在每一个释放 CO 2的开始的当前本地时间。 </li><li>放置的 CO 2气缸和释放系统进入的 CO 2圆筒夹持器（馈送槽）并引导喷嘴进入歧管。不要吸入进纸器中。 </li><li>打开开/关阀，释放的 CO 2，并记录开始释放的时间。后退几英尺远从馈线，并等待3分钟。 3分钟后，关掉释放的开/关阀和记录停止时刻。 </li><li>从送纸器中取出CO 2缸加释放系统。不要拧下释放系统的CO 2缸。握住CO 2缸温水（37〜43℃），浴缸。仅放置在汽缸中的水，而不是整个释放系统。 </li><lI&gt;一旦CO 2筒预热，从水中取出，并用干布，从它擦拭所有的水。称取CO 2缸版本的系统，并记录此作为最终质量。 </li><li>等待至少3分钟的下一版本之前。在3分钟的等待时间，不要让附近单位的任何动物或人。 A 90克Co 2缸可提供约3版本，以便使用多个气瓶，如果有3个以上的版本。当一个液压缸是空的，称量空筒，并继续与一个新的汽缸，如上所述。 </li><li>重复步骤4.3至4.9至少3次，标志着新的开始时间，结束时间，初始质量，以及每个版本的最终质量。 </li><li>最终发布后，至少等待3分钟让动物进入单位之前。完成后，拧下释放系统的CO 2缸。 </li></ol> 5.气体测量注:在气体测量，最近（在一个星期内）AHCS的校准是必需的。见步骤3，AHCS和4， 二氧化碳回收试验标定。确保动物的RFID标签很到位。 <ol><li>上电AHCS和离开30分钟做任何测量前的热身。 </li><li>位置AHCS使气流从谷仓球迷被允许进入料桶。等待2分钟。按FEED交货按钮并保持3秒，提供约50 g饲料的。直观地验证饲料已交付到饲料槽。 </li><li>在牛前辊AHCS。记录在实验笔记本电脑的时间。该装置将读取动物的RFID标签。 </li><li>饲料交付额外的5次超过5分钟的采样周期，间隔他们试图继续保持动物的头，在饲槽。如果额外的饲料是必需的（以保持动物的头进入料桶），记下它的实验笔记本。 </li><li>不E:进料/颗粒通常交付每50秒共6滴（300克/测量事件），得到5分单独测量周期。所述AHCS装有红外传感器来连续地监视动物的相对于进气歧管头​​的距离。这些数据随后被用于确定当动物的头是不是在位置和这些测量数据被丢弃周期。 </li><li>一旦5分钟取样期已过，拉AHCS远离动物和定位装置，使气流从谷仓球迷被允许进入料桶。等待2分钟通过该系统以冲洗空气并收集背景空气组合物的数据。 </li><li>重复步骤5.2至5.5更多的动物。 </li><li>重复取样在24小时的饲养周期的8倍，错开时间超过3天。下面取样时间表已成功地用于:0900，1500，和2100小时（取样天1），0300，1200，和1700小时（取样天2），0000，和0500小时（取样天3）。这种采样时间表将提供8个样品每动物和每个采样周期。采样时间可能因饲养和挤奶时间各不相同。 注意:当气体取样完成时，从该网页中检索发光数据。 </li></ol>

<ol>
	<li>Hristov, A. N., Gerber, P. J., Henderson, B., Makkar, P. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Mitigation of greenhouse gas emissions in livestock production &#8211; A review of technical options for non-CO2 emissions. , (2013).</li><li>Steinfeld, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Livestock&#8217;s long shadow &#8211; Environmental issues and options. , (2006).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009. , (2011).</li><li>Makkar, H. P. S., Vercoe, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Quantification of methane emission from ruminants, FAO/IAEA Publication. , 138 (2007).</li><li>Williams, S. R. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Background+matters+with+the+SF6+tracer+method+for+estimating+enteric+methane+emissions+from+dairy+cows:+A+critical+evaluation+of+the+SF6+procedure.">Background matters with the SF6 tracer method for estimating enteric methane emissions from dairy cows: A critical evaluation of the SF6 procedure.</a> Anim. Feed Sci. Technol. 170 (3-4), 265-276 (2011).</li><li>Storm, I. M. L. D., Hellwing, A. L. F., Nielsen, N. I., Madsen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+measuring+and+estimating+methane+emission+from+ruminants.">Methods for measuring and estimating methane emission from ruminants.</a> Animals. 2, 160-183 (2012).</li><li>Hristov, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitigation+of+methane+and+nitrous+oxide+emissions+from+animal+operations:+I.+A+review+of+enteric+methane+mitigation+options.">Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options.</a> J. Anim. Sci. 91 (9), 5045-5069 (2013).</li><li>Zimmerman, P., Zimmerman, S., Utsumi, S., Beede, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+user-friendly+online+system+to+quantitatively+measure+metabolic+gas+fluxes+from+ruminants.">Development of a user-friendly online system to quantitatively measure metabolic gas fluxes from ruminants.</a> J. Dairy Sci. 94, 760 (2011).</li><li>Hammond, K. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methane+emissions+from+growing+dairy+heifers+estimated+using+an+automated+head+chamber+(GreenFeed)+compared+to+respiration+chambers+or+SF6+techniques.">Methane emissions from growing dairy heifers estimated using an automated head chamber (GreenFeed) compared to respiration chambers or SF6 techniques.</a> Adv. Anim. Biosci. 4 (Pt 2), 391 (2013).</li><li>Huhtanen, P., Krizsan, S., Cabezas Garcia, E. H., Hetta, M., Gidlund, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repeatability+and+between+cow+variability+of+enteric+CH4+and+total+CO2+emissions.">Repeatability and between cow variability of enteric CH4 and total CO2 emissions.</a> Adv. Anim. Biosci. 4 (Pt 2), 588 (2013).</li><li>Zimmerman, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+and+system+for+monitoring+and+reducing+ruminant+methane+production.">Method and system for monitoring and reducing ruminant methane production.</a> US patent. , (2011).</li><li>Branco, A. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+technical+cashew+nut+shell+liquid+on+rumen+methane+production+and+lactation+performance+of+dairy+cows.">Effect of technical cashew nut shell liquid on rumen methane production and lactation performance of dairy cows.</a> J. Dairy Sci. 98, 4030-4040 (2015).</li><li>Dorich, C. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Short+communication:+Use+of+a+portable+automated+opencircuit+gas+quantification+system+and+the+sulfur+hexafluoride+tracer+technique+for+measuring+enteric+methane+emissions+in+Holstein+cows+fed+ad+libitum+or+restricted.">Short communication: Use of a portable automated opencircuit gas quantification system and the sulfur hexafluoride tracer technique for measuring enteric methane emissions in Holstein cows fed ad libitum or restricted.</a> J. Dairy Sci. 98, 2676-2681 (2015).</li><li>Hristov, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+inhibitor+persistently+decreased+enteric+methane+emission+from+dairy+cows+with+no+negative+effect+on+milk+production.">An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production.</a> Proc Nat Acad Sci USA. , (2015).</li></ol>

作者帕特里克·R·齐默尔曼和Scott R.齐默尔曼是C-锁公司共同拥有 （拉皮德城，SD），绿色饲料（AHCS）的制造商说明本条。

所述AHCS系统结合了动态外壳技术中，腔系统，以及用于甲烷和CO 2的质量流量测量示踪技术的元素。在数天的过程中，它收集多个样品从每只动物以限定平均日总气体质量通量。来识别动物和提供诱饵的正确量，RFID读取器被并入AHCS。 RFID标签被读取成动物开始将其头部插入送纸器。一旦动物识别，AHCS确定其是否有资格获得奖励的诱饵在一天中的特定时间（放牧或免费牛舍的应用程序）。每只动物的访问（基于红外传感器确定）的开始和结束时间被自动记录。诱饵递送系统是用来吸引动物AHCS周期性全天。通常，所述诱饵饲料造粒和可以含有草，苜蓿，粒浓缩物，糖蜜，和植物油。虽然动物访问AHCS，风扇拉风了它的头（约26升/分钟的速度），扫发出的CH 4和CO 2到进气歧管。空气流动的速率与一个热膜风速计在空气收集管的中间连续地测量。空气的连续的子样本被提取并传送到次级样品过滤，然后分成两个非分散红外分析仪，一个传感器对CO 2和一个用于CH 4。 AHCS还包括用于空气温度，空气湿度，诱饵降，系统电压，大气压力，丙烷流量，和头部位置的附加传感器。牧草和拖车式版本放牧系统包括一个杯形风速计（当地风速）和风向标（风向）。所有传感器数据被存储在本地的数据记录器和一个计算机，从而使AHCS自动地和独立地发挥作用。传感器数据也存储在内部标准USB（通用串行总线）存储器棒。 AHCS数据通常通过互联网链路传送，每小时一次，在那里它们被永久地记录在外部服务器。与互联网连接，用户可以远程登录到AHCS和控制单元，修改引诱时间表，并查看历史和实时数据，以及审查和监督AHCS功能。 总体而言，在美国宾夕法尼亚州立大学进行的实验表明，AHCS系统提供的甲烷和二氧化碳奶牛装在并列失速谷仓排放可靠的估计。 AHCS超过呼吸室的优点是，动物没有限制，并且是在其天然环境（即，在牧场），或可以自由移动（在自由牛舍）。 AHCS还建立比传统的呼吸室更便宜。此相对低的成本是非常重要的，特别是对CH 4的减轻研究在发展中国家。与SF 6跟踪比较ř方法，AHCS更易于操作，并且不需要复杂且昂贵的分析设备。也许AHCS的最明显的缺点，与商会和SF 6的方法（在放牧或自由牛舍环境中特别是）相比，是动物有主动接近单元，因此气体测量活动都依赖于动物访问。一天之内，这些动物的访问可能会或可能无法代表的CH 4产生的昼夜节律的。因此，在应用中，动物访问AHCS自愿，采样周期应足够长，或重复的足够次数。在宾夕法尼亚州立大学使用的领带摊位申请控制在24小时的饲养周期的数量和气体测量的时间分布，解决了这个问题。嗳气气体的过程中的供给周期（如在上述方案所示）足够采样为representati重要已经估计甲烷产量在牛的瘤胃中。饵饲料的过程中使用AHCS测量供给到动物的量在整体分析（即，必须添加到饲料被动物消耗的总金额），所以每单位进料的发光强度的DMI可以准确要考虑估计。在正常饲养条件下，所述饵料表示的奶牛的总的DMI和其作用，对瘤胃发酵的低于5％和CH 4的产生小。应该注意的是AHCS（和其它类似的系统）不会测量CH 4产生在动物的肠。后肠发酵，但是，有利于仅约3％的总甲烷排放量的在反刍动物7。 根据经验，测量有肠溶瘤胃气体生产中使用AHCS的几个重要组成部分:（1）动物必须习惯于诱饵进料（和AHCS），并具有吨ö喜欢它，以便接近和使用AHCS馈线;（2）动物的头，必须一路插入供给器，以便收集可靠的气体排放数据，（3）的AHCS校准程序，必须严格遵守，（4）具有足够的时间来收集采样个别动物之间的背景的 CH 4和CO 2的数据是重要的，特别是在领带或自由失速谷仓，和（5）是很重要的足够的数据被收集在一个采样周期（覆盖24小时内），以便通过AHCS产生的排数据代表实际的昼夜CH 4或CO 2排放量的动物。 对比测试，AHCS与建立CH 4测量技术支持了上述结论。例如，越来越小母牛的一项研究得出的结论是AHCS是能够从AHCS产生的牲畜和排放估算估算甲烷排放量的可比性由呼吸室 9而得到的值。这些作者指出，部署的AHCS单元和复制​​，必须仔细考虑，以确保足够数量的测量值获得。根据经验，8个采样的事件，交错，在3天时间内以覆盖24小时馈送周期（见协议以上）足以获得气体排放物的准确的测量，并在数据相对低的变异性（即，可接受的精度）。在与哺乳期奶牛的研究中，得出的结论是甲烷排放量由AHCS测量类似于从呼吸室和动物变异性衍生的文献值（11至12％的CV; 0.64〜0.81重复性）也内系列报道的呼吸室10。在最近发表的研究与泌乳牛，AHCS产生了较小的简历比SF 6方法（14.1至22.4％和16.0〜111％的SF 6）13 </SUP&gt;。在宾夕法尼亚州立大学，拥有48泌乳奶牛，在瘤胃甲烷产量抑制了30％（P &lt;0.001），进行了为期12周的实验中，我们得出的结论是AHCS和SF 6方法生产的类似CH 4排放结果:319 481克/每头牛每天（平均374克/ D; SEM = 15.9; CV = 13％）和345 485克/每头牛每天（平均396克/ D; SEM = 29.8; CV = 23 ％）为AHCS 和 SF 6， 分别为14。 总之，准确，但测量甲烷生产在瘤胃中的实用技术是对温室气体减排的努力取得成功至关重要。 AHCS是已被证实可提供肠溶CH 4和CO 2的排放量从肉牛和奶牛的可靠和准确的估算值的自动气体测量系统。

动物产品代表的温室气体（GHG）的全球排放量的显著来源，无论是直接产生甲烷和一氧化二氮（ 例如 ，肠道发酵和粪肥管理）或间接（ 比如 ，从进料，生产活动和转化森林到牧场或农田）。估计全球温室气体排放家畜贡献约7 1〜18％2变化，这取决于所使用的分析和方法的界限。在美国，牲畜为代表的温室气体排放总量的3.1％，2009年3。 肠道CH 4是最大的贡献者来自畜牧业的温室气体排放。因此，动物科学家们发现上缓解技术以减少肠道甲烷生产反刍动物集中他们的研究。在许多情况下，结果是有问题的科学价值，由于实验设计Ø不足R值测量方法1。因此，测量技术的准确度和精密度都严格温室气体减排研究的重要组成部分。大量文献都已经发表了关于这个话题在近几年4-7。有几种方法建立用于测量肠溶CH 4产生于反刍动物，包括呼吸室（高度准确的，但具有有限的适用性），示踪气体（六氟化硫; SF 6），和头腔室。虽然呼吸室被认为是"金标准"，用于测量瘤胃气体排放，其主要缺点是，动物的审判的数量通常是由于在某一特定研究机构提供商会在有限数量的限制。用于测量肠溶CH 4产生最实际和广泛使用的技术是对SF 6示踪气体的方法，最近，一个自动头室系统（AHCS，绿色饲料）将c一个监视器甲烷和CO 2的质量通量从8反刍动物的呼吸和嗳气气。无论是SF 6技术和AHCS使排放量要在自由放牧条件下或在自由和领带摊位谷仓大量动物的分析。的SF 6技术利用SF 6作为示踪气体，它是连续地从在呼出气体的样品的动物，收集的瘤胃插入渗透管，气体的分析适用于SF 6释放:CH 4比。 AHCS]是也基于使用示踪气体（丙烷）的自动化，头部室型系统。与呼吸腔室的方法，其中动物异常馈送和行为的条件下密闭，并通过SF 6示踪方法，该方法需要特殊的分析能力和设备（气体收集和 SF 6分析）以及大量的动物处理相比，AHCS是非-intrusive并且不太昂贵的掌握和操作。 AHCS的主要缺点包括不具代表性的采样（在应用，如放牧系统，其中，动物必须自愿访问单元），并使用诱饵饲料，这可能的气体测量期间表示多达动物的干物质摄取量的5％事件。最近的对比实验得出的结论是AHCS产生的排放率与那些使用呼吸室或SF 6技术9,10估计。 单机AHCS系统是围绕一个强大的自动进给器是易于运输通过手工或可被安装到装备有太阳能电池板（或其他电源），用于自主现场操作和长途旅行的拖车构成。该系统包括一个动物射频识别系统（RFID），一个诱饵系统，空气处理和测量系统，气体示踪系统，电子设备和通信系统，以及一个数据处理系统（&lt;STRONG&gt;图1）。更多细节可以在原专利文献11中找到。 下面介绍的例子AHCS操作协议是奶牛装在一个领带牛舍。该过程也适用于其他类型的容纳在类似设施牛（非哺乳期奶牛，小母牛，或肉牛）的。该实验的目的是证明AHCS的原理和操作为甲烷和二氧化碳从反刍动物排放的测量。

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>AHCS</td>
			<td>1</td>
			<td>C-Lock, Inc.</td>
			<td></td>
		</tr>
		<tr>
			<td>Zero, 100 N2</td>
			<td>1</td>
			<td>Air Liquide</td>
			<td>4 m3 sized tanks filled with&#160; 13,790 kPa</td>
		</tr>
		<tr>
			<td>Span, 0.15% CH4 and 1% CO2</td>
			<td>1</td>
			<td>Air Liquide</td>
			<td>4 m3 sized tanks filled with 13,790 kPa</td>
		</tr>
		<tr>
			<td>Gas sampling bag</td>
			<td>2</td>
			<td>SKC, Inc.</td>
			<td>FlexFoil&#174; PLUS Breath-gas analysis bags</td>
		</tr>
		<tr>
			<td>Gas regulator</td>
			<td>2</td>
			<td>Scott Gasses</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2 cylinder</td>
			<td>6</td>
			<td>JT</td>
			<td>90 g CO2 tanks</td>
		</tr>
		<tr>
			<td>Mass scale</td>
			<td>1</td>
			<td>A&#38;D EJ6100</td>
			<td>&#62; 4 kg, with 0.1 g resolution</td>
		</tr>
		<tr>
			<td>Propane cylinder 485 mL</td>
			<td>1</td>
			<td>Coleman</td>
			<td></td>
		</tr>
		<tr>
			<td>ISO 11784/11785 button ear tag</td>
			<td>40</td>
			<td>Allflex USA</td>
			<td>One tag per animal</td>
		</tr>
		<tr>
			<td>Alleyway (for free-stalls, tie-stalls)</td>
			<td>2</td>
			<td>Behlen Country</td>
			<td>One alleyway per unit</td>
		</tr>
		<tr>
			<td>30 m AC extension cord</td>
			<td>1</td>
			<td>HDX</td>
			<td></td>
		</tr>
		<tr>
			<td>A container with warm water (37-43&#176;C)</td>
			<td>1</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Stopwatch (sec)</td>
			<td>1</td>
			<td>N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

the use of an automated system (greenfeed) to monitor enteric methane and carbon dioxide emissions from ruminant animals

反刍动物（驯养的或野生）发射甲烷 （CH 4）通过肠道发酵在他们的消化道和从储存期间粪肥的分解。这些过程的温室气体（GHG）从动物生产系统排放的主要来源。用于测量肠溶CH 4技术从直接测量不同（呼吸腔室，这是高度精确的，但具有有限的适用性）各种间接方法（监听器，激光技术，这是实际的，但具有可变的准确度）。六氟化硫（SF 6）示踪气体方法是常用的动物科学家，最近来衡量肠道甲烷生产，应用的自动头腔系统（AHCS）（绿色饲料，C-锁公司，拉皮德城的， SD），这是该实验的焦点，一直在增长。 AHCS是一个自动化的系统来监控甲烷和二氧化碳（CO 2）从质量通量呼吸反刍动物。在一个典型的AHCS操作，小批量下料的饲料被分配到各个动物每天吸引他们到AHCS多次。当动物访问AHCS，风扇系统能让空气经过动物的枪口入进气歧管，并通过空气收集管，其中连续气流速率进行测量。空气的子样本被泵出管的成非色散红外线传感器的 CH 4和CO 2浓度的连续测量。 AHCS对呼吸室或SF 6场的比较表明，AHCS产生重复和精确的CH 4排放的结果，前提是动物参观AHCS都足以使排放量估计有代表性瘤胃产气的昼夜节律。在这里，我们演示了如何使用AHCS的从给予控制饮食或补充工业级腰果饮食奶牛4通量测量二氧化碳和甲烷外壳液体。

<img alt="图1" src="/files/ftp_upload/52904/52904fig1.jpg" /> 图1:自动头部室系统（AHCS，绿色饲料）的用于测量CH 4产生在反刍动物的组件。 甲烷产生在瘤胃是衬底依赖性微生物过程7。生产中的CH 4和CO 2的增加后的动物饲喂，降低其后。 图2显示从奶牛自由进食（由AN赫里斯托夫，宾夕法尼亚州立大学未公布的数据）增加的CH 4产生在约0600 小时 。 <img alt="图2" src="/files/ftp_upload/52904/52904fig2.jpg" /> 图2:日CH从测量喂一次每日奶牛4排放量使用AHCS（误差棒代表SE;数据来源AN赫里斯托夫，笔nsylvania州立大学）。 在此图中的误差线代表过程的取样事件（包括多个嗳气循环）变异的CH 4排放 。显而易见的是，在一些情况下（大约0400和0900小时），变异性是由于改变呼出的气体CH 4的浓度大。它同样清楚的是甲烷排放量喂食后增加（这是周围0600小时在这个例子中）。每日平均CH 4排放 （ 即 ，平均13个测量事件）的这头牛是727±22.9克/天，或26克/公斤时，每千克日粮干物质采食量（DMI）的表达。 为了证明CH的范围从一组使用AHCS测量泌乳奶牛4排放量，我们包括在宾夕法尼亚州立大学最近进行的一项交叉设计试验，采用工业级腰果壳液为CH 4数据<html>缓解剂（ 表1）。审讯是在8头泌乳荷斯坦奶牛每21天2实验阶段。在每个周期的最后一周收集甲烷的数据。甲烷排放数据不是从一头牛收集在第1期和那头牛数据也没有时间用实验2的细节可以在布兰科等人 12发现。在这项研究中的平均CO 2的排放量为每天超过18,000个克/牛，或634克/千克的DMI。平均CH 4的排放为这组母牛为五百二十三克/天或20克/公斤的DMI，这是类似的平均甲烷排放报告了超过370处理装置（19.1±0.43克/公斤的DMI）7的数据集。在研究表 1中所示，与对照组相比，工业级腰果壳油倾向于由约5％（P = 0.08）12，以减少甲烷产量的奶牛瘤胃。 e_content"&gt; <img alt="表1" src="/files/ftp_upload/52904/52904table1.jpg" />

Watch this Scientific Journal Video about The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals at JoVE.com

The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

自动系统（绿色饲料）的用于监视肠道的甲烷和二氧化碳从反刍动物排放

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during ...

the-use-an-automated-system-greenfeed-to-monitor-enteric-methane

Universidad de Cartagena UDEC

Research

JoVE Journal

Environment

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

21.7K 次观看.  Pennsylvania State University. Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

视频: The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA libraries are needed for optimal results from next-generation sequencing. Environmental samples such as water may have low quality and quantities of DNA as well as contaminants that co-precipitate with DNA. The mechanical and enzymatic processes involved in extraction and library preparation may further damage the DNA. Gel size selection enables purification and recovery of DNA fragments of a defined size for sequencing applications. Nevertheless, this task is one of the most time-consuming steps in the DNA library preparation workflow. The protocol described here enables complete automation of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments. 
In this study, we describe a high-throughput approach to prepare high quality DNA libraries from freshwater samples that can be applied also to other environmental samples. We used an indirect approach to concentrate bacterial cells from environmental freshwater samples; DNA was extracted using a commercially available DNA extraction kit, and DNA libraries were prepared using a commercial transposon-based protocol. DNA fragments of 500 to 800 bp were gel size selected using Ranger Technology, an automated electrophoresis workstation. Sequencing of the size-selected DNA libraries demonstrated significant improvements to read length and quality of the sequencing reads.

This manuscript describes an automated gel size selection approach for purifying DNA fragments for next-generation sequencing. The Ranger Technology provides complete automation of the entire process of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments allowing for high-throughput and high quality next-generation sequencing libraries.

自动凝胶尺寸选择，以提高下一代测序文库的质量，从环境水样准备

Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA ...

科研

环境科学

Implementation of Portable Emissions Measurement Systems (PEMS) for the Real-driving Emissions (RDE) Regulation in Europe

Vehicles are tested in controlled and relatively narrow laboratory conditions to determine their official emission values and reference fuel consumption. However, on the road, ambient and driving conditions can vary over a wide range, sometimes causing emissions to be higher than those measured in the laboratory. For this reason, the European Commission has developed a complementary Real-Driving Emissions (RDE) test procedure using the Portable Emissions Measurement Systems (PEMS) to verify gaseous pollutant and particle number emissions during a wide range of normal operating conditions on the road. This paper presents the newly-adopted RDE test procedure, differentiating six steps: 1) vehicle selection, 2) vehicle preparation, 3) trip design, 4) trip execution, 5) trip verification, and 6) calculation of emissions. Of these steps, vehicle preparation and trip execution are described in greater detail. Examples of trip verification and the calculations of emissions are given.

Implementation of Portable Emissions Measurement Systems PEMS for the Real-driving Emissions RDE Regulation in Europe

The European Commission has developed a Real-Driving Emissions (RDE) test procedure to verify pollutant emissions during real-world vehicle operation using the Portable Emissions Measurement Systems (PEMS). This paper presents the experimental procedures required by the newly-adopted RDE test.

便携式排放测量系统（PEMS）在欧洲的真实驾驶排放（RDE）规例的执行情况

Vehicles are tested in controlled and relatively narrow laboratory conditions to determine their official emission values and reference fuel consumption. ...

Methods of Soil Resampling to Monitor Changes in the Chemical Concentrations of Forest Soils

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scientific community. The objective of this protocol is therefore to synthesize the latest information on methods of soil resampling in a format that can be used to design and implement a soil monitoring program. Successful monitoring of forest soils requires that a study unit be defined within an area of forested land that can be characterized with replicate sampling locations. A resampling interval of 5 years is recommended, but if monitoring is done to evaluate a specific environmental driver, the rate of change expected in that driver should be taken into consideration. Here, we show that the sampling of the profile can be done by horizon where boundaries can be clearly identified and horizons are sufficiently thick to remove soil without contamination from horizons above or below. Otherwise, sampling can be done by depth interval. Archiving of sample for future reanalysis is a key step in avoiding analytical bias and providing the opportunity for additional analyses as new questions arise.

Repeated soil sampling has recently been shown to be an effective way to monitor forest soil change over years and decades. To support its use, a protocol is presented that synthesizes the latest information on soil resampling methods to aid in the design and implementation of successful soil monitoring programs.

土壤重采样的方法监控森林土壤的化学浓度的变化

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental ...

Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. Therefore, it is highly desirable to remove biofilms from surfaces. Many studies on CO2 aerosol cleaning have employed nitrogen purges to increase biofilm removal efficiency by reducing the moisture condensation generated during the cleaning. However, in this study, periodic jets of CO2 aerosols without nitrogen purges were used to remove Pseudomonas putida biofilms from polished stainless steel surfaces. CO2 aerosols are mixtures of solid and gaseous CO2 and are generated when high-pressure CO2 gas is adiabatically expanded through a nozzle. These high-speed aerosols were applied to a biofilm that had been grown for 24 hr. The removal efficiency ranged from 90.36% to 98.29% and was evaluated by measuring the fluorescence intensity of the biofilm as the treatment time was varied from 16 sec to 88 sec. We also performed experiments to compare the removal efficiencies with and without nitrogen purges; the measured biofilm removal efficiencies were not significantly different from each other (t-test, p &gt; 0.55). Therefore, this technique can be used to clean various bio-contaminated surfaces within one minute.

Biofilms on surfaces can be effectively and rapidly removed by using a periodic jet of carbon dioxide aerosols without a nitrogen purge.

去除生物膜使用二氧化碳气溶胶没有氮气吹扫

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. ...

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence the oxidizing capacity of the atmosphere through interactions with ozone and hydroxyl radicals. The main sink of NOx is the formation and deposition of nitric acid, a component of acid rain and a bioavailable nutrient. NOx is emitted from a mixture of natural and anthropogenic sources, which vary in space and time. The collocation of multiple sources and the short lifetime of NOx make it challenging to quantitatively constrain the influence of different emission sources and their impacts on the environment. Nitrogen isotopes of NOx have been suggested to vary amongst different sources, representing a potentially powerful tool to understand the sources and transport of NOx. However, previous methods of collecting atmospheric NOx integrate over long (week to month) time spans and are not validated for the efficient collection of NOx in relevant, diverse field conditions. We report on a new, highly efficient field-based system that collects atmospheric NOx for isotope analysis at a time resolution between 30 min and 2 hr. This method collects gaseous NOx in solution as nitrate with 100% efficiency under a variety of conditions. Protocols are presented for collecting air in urban settings under both stationary and mobile conditions. We detail the advantages and limitations of the method and demonstrate its application in the field. Data from several deployments are shown to 1) evaluate field-based collection efficiency by comparisons with in situ NOx concentration measurements, 2) test the stability of stored solutions before processing, 3) quantify in situ reproducibility in a variety of urban settings, and 4) demonstrate the range of N isotopes of NOx detected in ambient urban air and on heavily traveled roadways.

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Previous work suggests that the nitrogen isotopic composition of atmospheric nitrogen oxides might distinguish the influence of different sources in the environment. We report on an automated, mobile, field-based method for the high collection efficiency of atmospheric NOx for N isotopic analysis at an hourly time resolution.

自动化，高清晰度移动采集系统对NO的氮同位素分析<sub系列&gt; X</sub

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence ...

Controlled-release of Chlorine Dioxide in a Perforated Packaging System to Extend the Storage Life and Improve the Safety of Grape Tomatoes

A controlled-release chlorine dioxide (ClO2) pouch was developed by sealing a slurry form of ClO2 into semipermeable polymer film; the release properties of the pouch were monitored in containers with or without fruit. The pouch was affixed to the inside of a perforated clamshell containing grape tomatoes, and the effect on microbial population, firmness, and weight loss was evaluated during a 14 day storage period at 20 &#176;C. Within 3 days, the ClO2 concentration in the clamshells reached 3.5 ppm and remained constant until day 10. Thereafter, it decreased to 2 ppm by day 14. The ClO2 pouch exhibited strong antimicrobial activity, reducing Escherichia coli populations by 3.08 log CFU/g and Alternaria alternata populations by 2.85 log CFU/g after 14 days of storage. The ClO2 treatment also reduced softening and weight loss and extended the overall shelf life of the tomatoes. Our results suggest that ClO2 treatment is useful for extending the shelf life and improving the microbial safety of tomatoes during storage without impairing their quality.

Here, we describe a protocol for the application of a novel, slow-release ClO2 product that reduces spoilage and extends the shelf life of fresh fruit. The slow-release ClO2 product was added to standard commercial grape tomato packaging and tested against Escherichia coli and Alternaria alternata.

在穿孔的包装系统二氧化氯的控释，延长贮藏寿命，提高葡萄番茄的安全

A controlled-release chlorine dioxide (ClO2) pouch was developed by sealing a slurry form of ClO2 into semipermeable polymer film; the release properties ...

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 &#176;C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A method for measuring the rheology of crude oil in equilibrium with carbon dioxide at reservoir conditions is presented.

与CO平衡的原油流变学测量<sub&gt; 2</sub&gt;在水库条件

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The ...

The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus area. Biomass capacitance plays an integral role in the avoidance of hydraulic impairment to transpiration. However, high temporal resolution measurements of dynamic changes in the hydraulic capacitance of large trees are rare. Here, we present procedures for the calibration and use of capacitance sensors, typically used to monitor soil water content, to measure the volumetric water content in trees in the field. Frequency domain reflectometry-style observations are sensitive to the density of the media being studied. Therefore, it is necessary to perform species-specific calibrations to convert from the sensor-reported values of dielectric permittivity to volumetric water content. Calibration is performed on a harvested branch or stem cut into segments that are dried or re-hydrated to produce a full range of water contents used to generate a best-fit regression with sensor observations. Sensors are inserted into calibration segments or installed in trees after pre-drilling holes to a tolerance fit using a fabricated template to ensure proper drill alignment. Special care is taken to ensure that sensor tines make good contact with the surrounding media, while allowing them to be inserted without excessive force. Volumetric water content dynamics observed via the presented methodology align with sap flow measurements recorded using thermal dissipation techniques and environmental forcing data. Biomass water content data can be used to observe the onset of water stress, drought response and recovery, and has the potential to be applied to the calibration and evaluation of new plant-level hydrodynamics models, as well as to the partitioning of remotely sensed moisture products into above- and belowground components.

The hydraulic capacitance of biomass is a key component of the vegetation water budget, which serves as a buffer against short and long-term drought stresses. Here, we present a protocol for the calibration and use of soil moisture capacitance sensors to monitor water content in the stems of large trees.

电容式传感器监测林木茎含水量的标定及应用

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus ...

A Video Surveillance System to Monitor Breeding Colonies of Common Terns (Sterna Hirundo)

Many waterbird populations have faced declines over the last century, including the common tern (Sterna hirundo), a waterbird species with a widespread breeding distribution, that has been recently listed as endangered in some habitats of its range. Waterbird monitoring programs exist to track populations through time; however, some of the more intensive approaches require entering colonies and can be disruptive to nesting populations. This paper describes a protocol that utilizes a minimally invasive surveillance system to continuously monitor common tern nesting behavior in typical ground-nesting colonies. The video monitoring system utilizes wireless cameras focused on individual nests as well as over the colony as a whole, and allows for observation without entering the colony. The video system is powered with several 12 V car batteries that are continuously recharged using solar panels. Footage is recorded using a digital video recorder (DVR) connected to a hard drive, which can be replaced when full. The DVR may be placed outside of the colony to reduce disturbance. In this study, 3,624 h of footage recorded over 63 days in weather conditions ranging from 12.8 &#176;C to 35.0 &#176;C produced 3,006 h (83%) of usable behavioral data. The types of data retrieved from the recorded video can vary; we used it to detect external disturbances and measure nesting behavior during incubation. Although the protocol detailed here was designed for ground-nesting waterbirds, the principal system could easily be modified to accommodate alternative scenarios, such as colonial arboreal nesting species, making it widely applicable to a variety of research needs.

A Video Surveillance System to Monitor Breeding Colonies of Common Terns Sterna Hirundo

This paper describes a protocol that uses a remote video monitoring surveillance system to continuously monitor breeding colonies of ground-nesting waterbirds. The system includes five cameras monitoring individual nests and one camera monitoring the colony as a whole, and is powered by car batteries that are recharged via solar panels.

监测常见燕鸥繁殖菌落的视频监控系统 (燕鸥家燕)

Many waterbird populations have faced declines over the last century, including the common tern (Sterna hirundo), a waterbird species with a widespread ...

Measuring Stolons and Rhizomes of Turfgrasses Using a Digital Image Analysis System

Length and diameter of stolons or rhizomes are usually measured using simple rulers and calipers. This procedure is slow and laborious, so it is often used on a limited number of stolons or rhizomes. For this reason, these traits are limited in their use for morphological characterization of plants. The use of digital image analysis software technology may overcome measurement errors due to human mistakes, which tend to increase as the number and size of samples also increase. The protocol can be used for any kind of crop but is particularly suitable for forage or grasses, where plants are small and numerous. Turf samples consist of aboveground biomass and an upper soil layer to the depth of maximum rhizome development, depending on the species of interest. In studies, samples are washed from the soil, and stolons/rhizomes are cleaned by hand before analysis by digital image analysis software. The samples are further dried in a laboratory heating oven to measure dry weight; therefore, for each sample, the resultant data are total length, total dry weight, and average diameter. Scanned images can be corrected before analysis by excluding visible extraneous parts, such as remaining roots or leaves not removed with the cleaning process. Indeed, these fragments normally have much smaller diameters than stolons or rhizomes, so they can be easily excluded from analysis by fixing the minimum diameter below which objects are not considered. Stolon or rhizome density per unit area can then be calculated based on sample size. The advantage of this method is quick and efficient measurement of the length and average diameter of large sample numbers of stolons or rhizomes.

A software-based image analysis system provides an alternative method to study the morphology of stoloniferous and rhizomatous species. This protocol permits measurement of the length and diameter of stolons and rhizomes and can be applied to samples with a large amount of biomass and to a wide variety of species.

利用数字图像分析系统测量草坪的茎和根状茎

Length and diameter of stolons or rhizomes are usually measured using simple rulers and calipers. This procedure is slow and laborious, so it is often ...

自动系统（绿色饲料）的用于监视肠道的甲烷和二氧化碳从反刍动物排放

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