Abstract
Enteric fermentation is the largest source of methane emissions in the United States, with beef cattle representing 71 percent of total enteric methane emissions in 2021. Approximately 87% of the enteric methane produced from US beef cattle comes from animals not housed in feedlots, thus significantly opportunity lies in development and delivery of mitigation solutions to grazing situations. Mitigating methane emissions can be expressed in two ways: on an emissions intensity basis (i.e., methane per kg of beef) or in absolute terms (i.e., methane emissions from the entire beef system). Mitigation solutions that reduce absolute or total emissions consistently are currently limited or in the case of higher concentrate diets in finishing cattle, already widely used. Genetic selection is a promising solution to mitigate enteric methane emissions; however, standardization of phenotype collection is required, as methane emissions estimates can be influenced by a wide array of measurement errors and methodological choices by investigators. Economically viable, practical, and scalable solutions are needed. Researchers and extension professionals should provide objective guidance to cattle producers and others in the cattle industry on the costs and benefits of the variety of potential enteric methane mitigation solutions.