Dietary additives to control methanogenesis in the rumen

Three approaches to decrease ruminal methanogenesis which vary from commercial accepted (yeast) to well verified but yet to enter widespread practical usage (organic acids) to an approach which although theoretically sound has yet to be substantively verified (plant extracts) are considered. Likely costs, benefits, both in terms of decreased methane and enhanced farmer profitability, and regulatory barriers to use these additives are considered. No clear favoured technology is identified; however, it is clear that the ultimate success of any of these approaches on reducing methanogenesis will rest not only on their biological efficacy but also with their economic impact.