摘要：Dairy cattle farming contributes significantly to greenhouse gas (GHG) emissions through methane (CH<sub>4</sub>) from enteric fermentation. To complement global efforts to mitigate climate change, there is a need for accurate estimations of GHG emissions using country-specific emission factors (EFs). The objective of this study was to develop national EFs for the estimation of CH<sub>4</sub> emissions from enteric fermentation in South Korean dairy cattle. Information on dairy cattle herd characteristics, diet, and management practices specific to South Korean dairy cattle farming was obtained. Enteric CH<sub>4</sub> EFs were estimated according to the 2019 refinement of the 2006 Intergovernmental Panel on Climate Change (IPCC) using the Tier 2 approach. Three animal subcategories were considered according to age: milking cows >2 years, 650 kg body weight (BW); heifers 1–2 years, 473 kg BW; and growing animals <1 year, 167 kg BW. The estimated enteric CH<sub>4</sub> EFs for milking cows, heifers, and growing animals, were 139, 83 and 33 kg/head/year, respectively. Currently, the Republic of Korea adopts the Tier 1 default enteric CH<sub>4</sub> EFs from the North America region for GHG inventory reporting. Compared with the generic Tier 1 default EF of 138 (kg CH<sub>4</sub>/head/year) proposed by the 2019 refinement to the 2006 IPCC guidelines for high-milking cows, our suggested value for milking cows was very similar (139 kg CH<sub>4</sub> /head/year) and different to heifers and growing animals EFs. In addition, enteric CH<sub>4</sub> EFs were strongly correlated with the feed digestibility, level of milk production, and CH<sub>4</sub> conversion rate. The adoption of the newly developed EFs for dairy cattle in the next national GHG inventory would lead to a potential total GHG reduction from the South Korean dairy sector of 97,000 tons of carbon dioxide-equivalent per year (8%). The outcome of this study underscores the importance of obtaining country-specific EFs to estimate national enteric CH<sub>4</sub> emissions, which can further support the assessment of mitigation actions.
