Research advances on enteric methane emission from ruminants in natural grazing system

In recent years, extreme weather events including extreme precipitation, extreme drought, heat wave, and extreme low temperature have occurred frequently around the world. This is mainly due to global warming caused by greenhouse gases produced by human activities. Therefore, it is the shared goal of all countries to achieve carbon neutrality, increased climate resilience, and mitigated climate changes. Methane (CH 4 ) is the second most important greenhouse gas after carbon dioxide (CO 2 ), but its warming potential is stronger. Methane from enteric fermentation in ruminants not only affects the environment, but also represents the loss of feed energy. As one of the important sources of CH 4 emission, extensive livestock systems have attracted much attention in recent years because of their impact on climate changes. This article mainly introduces the CH 4 emission of ruminants in the extensive livestock systems, and the mitigation strategies and management practices. It also introduces several accounting methods and monitoring technologies for CH 4 emission of ruminants, aiming to provide technical guidance for the medium- and long-term strategy of reducing the carbon footprint of livestock production systems and achieving the “double carbon” goal.