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标题：A time-series of methane and carbon dioxide production from dairy cows during a period of dietary transition
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作者：Mark A. Lee ; Allison Todd ; Mark A. Sutton 等
期刊名称：Cogent Environmental Science
电子版ISSN：2331-1843
出版年度：2017
卷号：3
期号：1
页码：1385693
DOI：10.1080/23311843.2017.1385693
语种：English
出版社：Taylor and Francis Ltd
摘要：Abstract Emissions from dairy farms are contributing to the increased concentrations of greenhouse gases which are linked to recent climate change. Altering diets has been proposed as a greenhouse gas mitigation strategy in dairy systems. The magnitude of mitigation and the time taken for cows to adapt to new diets has not been comprehensively quantified. Methane (CH₄) and carbon dioxide (CO₂) produced by dairy cows was measured for six weeks using the sulphur hexafluoride tracer technique following a change in diet; from barley straw and protein supplements to grazed grass. CH₄ and CO₂ production increased linearly as the animals adapted to their new diets, however, production did not reach an asymptote six weeks into the grazing period. This suggested that metabolic activity and greenhouse gas emissions may not have been at their maximum. There was substantial variation between individuals with high emitting cows producing four times more CH₄ than low producing cows. Cows which produced greater amounts of CH₄ consistently also produced greater CO₂. We demonstrate that feeding regime plays an important role in determining greenhouse gas emissions and we highlight that transition periods in greenhouse gas models and future experiments must be sufficiently large to allow for adaptation.
关键词：climate change ; dairy ; dry period ; enteric methane ; greenhouse gases ; transition