Methane Emission Factors From Indigenous Cattle Breed In Smallholder Livestock Production Systems In Ethiopia

The objective of this study was to estimate methane (CH4) emission factor from enteric fermentation and manure management in indigenous cattle in Ethiopian highland using intergovernmental panel on climate change (IPCC) tier 2 methodologies. A survey was conducted in 2018 using questionnaire regarding cattle management, feed and feeding system on 50 smallholder farmers in central Ethiopia. Information was also collected from literature and contact with federal and regional research institutions. This information was used as input in the IPCC tier 2 methodologies for estimation of CH4 emission factors for eight cattle sub-categories. Results indicated that enteric CH4 emission factors were estimated to be 65, 49, 37, 56, 66, 58, 63 and 11 for mature lactating cows, dry cows, heifers (2-3 years), growing females (1-2 years), draught oxen, mature breeding males, growing males (1-2 years) and calves (< 1 year), respectively. Manure management CH4 emission factors were 4.97, 3.77, 2.86, 4.33, 5.06, 4.47, 4.88 and 1.71 kg/head/year for mature lactating cows, dry cows, heifers (2-3 years), growing females (1-2 years), draught oxen, mature breeding males, growing males (1-2 years) and calves (< 1 year), respectively. The present estimate on enteric CH4 emission factor using tier 2 methodologies in present study ranged from 11 to 66 kg per head per year while manure management CH4 emission factor ranged from 1.71 to 5 kg per head per year. These values are higher than the IPCC 2006 tier 1 default values for African region. However, present work’s estimates are within a range of literature reports for other cattle in different countries. Further research is required to improve emission factors estimates using primary data on live weight, animal performance and feed characterization.