Evaluation of greenhouse gas emissions from Bonga and Menz sheep breeds managed under community-based breeding program

Assemu T Tesfa, Mengistie Taye, Aynalem Haile, Zerihun Nigussie, Dina Najjar, Shigdaf Mekuriaw, Shimels E. Wassie, Shanbel Yeshaw, Zelalem Abate Ambecho, Chekole Demis, Tesfaye Getachew, Suzanne Van Dijk, Andreas Wilkes, Dawit Solomon. (9/5/2026). Evaluation of greenhouse gas emissions from Bonga and Menz sheep breeds managed under community-based breeding program. Scientific Reports, 16.

Abstract

Livestock systems contribute substantially to Greenhouse Gas (GHG) emissions, highlighting the need for interventions that enhance productivity while lowering environmental impact. This study assessed GHG emissions and emission intensity (EI) in Ethiopian Menz and Bonga sheep managed under Community-Based Breeding Programs (CBBP) compared with non-CBBP flocks. Using FAO’s GLEAM-i model with long-term performance data (2009–2022) and surveys of 321 households, we found that CBBPs reduced total emissions by 14.56% in Menz and 7.04% in Bonga sheep, while protein output rose by 42% and 2%, respectively. EI declined by 21.49% in Menz and 6.29% in Bonga. At the household level, CBBP flocks achieved markedly lower EI, 39.39% in Menz and 30.68% in Bonga, despite higher absolute emissions from larger flocks. Methane, mainly from enteric fermentation, accounted for a higher proportion compared to other GHG gases. EI was positively associated with reproductive inefficiencies while negatively associated with growth traits, underscoring key levers for mitigation. These results demonstrate that CBBPs deliver both productivity gains and environmental co-benefits, offering a scalable model for climate-smart small ruminant development with relevance beyond Ethiopia.