Estimation of methane emission factor for enteric fermentation of growing-finishing Hanwoo steers using the IPCC Tier 2 approach

Department of Animal Biosystem Sciences, Chungnam National University, Daejeon, South Korea
Subject Areas
Agricultural Science, Biosphere Interactions, Climate Change Biology, Environmental Sciences
Enteric Fermentation, Methane Emission Factor, Hanwoo (Korean native cattle), IPCC Tier 2
© 2015 Jo et al.
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Cite this article
Jo N, Kim J, Seo S. 2015. Estimation of methane emission factor for enteric fermentation of growing-finishing Hanwoo steers using the IPCC Tier 2 approach. PeerJ PrePrints 3:e1285v1


Enteric methane (CH4) production by cattle is one of the major sources of greenhouse gas (GHG) emissions in the livestock sector. In order to develop a national GHG inventory and establish a mitigation strategy for GHG emissions from livestock production, accurate estimation of enteric CH4 production by cattle is required. In this regard, the Tier 2 method in the Intergovernmental Panel on Climate Change (IPCC) guidelines is the most widely used. The objective of this study was to estimate and evaluate the CH4 emission factor (MEF; kg CH4/head/year) for enteric fermentation using the IPCC Tier 2 method in Hanwoo steers, a dominant beef production species in Korea raised in a unique feeding system (e.g., a duration of > 16 months in a feedlot). Methane emission factor for enteric fermentation was estimated using the IPCC Tier 2 method (T2) on Korea- and Hanwoo-specific data obtained from the literature. The MEF values were also estimated and compared using the IPCC Tier 1 (T1), the IPCC Tier 2 methodology with estimated gross energy GE intake based on actual dry matter intake (T2DMI), and the Japanese Tier 3 method (JT3). JT3 was chosen due to the similarity in the beef cattle production system between the two countries. Estimated MEF using T2 were 43.4, 33.9, and 36.2 kg CH4/head/year for the growing, finishing, and overall period, respectively. The overall MEF estimated using T2 was 23% lower than the estimate by T1 (47.0 kg CH4/head/year). There were significant differences in the estimated MEF for enteric fermentation of Hanwoo steers among the T2, T2DMI, and JT3 methods. JT3 estimated the highest values in all periods possibly due to overestimation of the conversion ratio of feed energy to CH4. No significant difference was found in the overall MEF of Hanwoo steers between T2 and T2DMI. However, T2DMI estimated 8% higher and 14% lower MEF than T2 for the growing and finishing period, respectively, mainly because the IPCC Tier 2 model significantly over-predicts the GE intake of Hanwoo steers at the high level of intake. The IPCC Tier 2 methodology is preferred to IPCC Tier 1 in estimating the MEF for enteric fermentation of Hanwoo steers, and the DMI model for Japanese cattle can be used to predict DMI of Hanwoo steers. In order to reduce the uncertainty of the estimates and search for a better mitigation strategy, however, development of a country-specific methodology and parameter estimates for enteric CH4 production of Hanwoo is required.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Table S1-4 of the animal and diet characteristics in this study

The animal and diet characteristics required to estimate the value (e.g., net energy requirements and gross energy intake and methane emission factor) were obtained from Kim et al. (2005), where a comprehensive feeding trial with 90 Hanwoo steers (three treatment means [n = 30] for 22 months) was conducted in a typical commercial farm throughout the feeding period.

DOI: 10.7287/peerj.preprints.1285v1/supp-1