Mechanisms for competitively reducing ruminal methanogenesis

Methane production is the principal end use of hydrogen gas derived by phosphoroclastic reactions or the release of protons from reducing equivalents by hydrogenases in the rumen. It should therefore be possible to reduce methanogenesis by (1) inhibiting H-2 liberating reactions, (2) promoting alternative reactions which accept H+ during reoxidation of reducing equivalents, and (3) promoting alternative H-2-using reactions. Strategies to reduce methanogenesis by these means are discussed. Particular attention is given to increasing synthesis of propionate and long chain fatty acids in the rumen, to acetogenesis, and to the actions of chemicals such as monensin and dietary fatty acids.