Methane emissions from indigenous nitrogen-efficient bovidae are overestimated

Livestock are vital for global food security, but are a significant source of methane, a greenhouse gas. Breeding for highly efficient nitrogen utilization and lower emissions is therefore a key goal for sustainable agriculture. Here we compared these traits across wild, indigenous, crossbred, and improved bovines via an extensive meta-analysis, supplemented with measurements of 150 yaks. Our results revealed that indigenous bovine produce less methane and have lower urinary nitrogen loss than improved breeds, indicating superior feed conversion and nitrogen efficiency. Notably, crossbreeds also produce significantly less methane, revealing a hybrid advantage for sustainable breeding. Furthermore, our direct measurements showed that methane emissions from yaks were 39% lower than predicted by Intergovernmental Panel on Climate Change Tier2 models, a pattern of overestimation also evident in other indigenous bovines. These findings reveal that well-adapted indigenous breeds are crucial genetic resources, highlighting the need for breed-specific data to guide global mitigation efforts. Indigenous and crossbred bovines produce less methane and consume nitrogen more efficiently than improved bovines, according to a meta-analysis combined with measurements of methane emissions from yaks in China.