Reducing enteric methane emissions from ruminants: challenges, solutions and perspectives at the animal and system levels

Abstract

Reducing enteric methane emissions from ruminant livestock is a common goal of many countries to limit global warming. While direct measurements of enteric methane emissions are limited to a small number of animals, indirect predictive methods based on milk or feces can now be used to assess emissions from large numbers of animals in a variety of contexts. These approaches allow the development of genetic selection models and management practices associated with lower methane emissions for small and large ruminants. A better understanding of the relationships between rumen microbial diversity and the ruminant (host) will help to identify new solutions for modulating rumen microbial populations and hydrogen fluxes, with the aim of reducing methane emissions while maintaining animal production and health. Ruminant diets and herd management are important ways to reduce enteric methane emissions, but the practices are not always suitable for the different pedoclimatic contexts, particularly in hot regions. Trade-off must be evaluated to identify combinations of levers that can reduce enteric methane emissions without compromising the health of animals and the ecosystem services associated with ruminant livestock systems.