A mechanistic model of hydrogen–methanogen dynamics in the rumen

• Model describes growth of rumen methanogens in relation to dissolved hydrogen.
• Explicit depictions of methanogen population and dissolved hydrogen pool.
• Model behaves according to biological expectations.
• Can be expanded to model multiple methanogen species with different characteristics.
• Hydrogen pool allows future incorporation of hydrogen feedback on fermentation.

Existing mathematical models to estimate methane production in the rumen are based on calculation of hydrogen balances without considering the presence of methanogens. In this study, a mechanistic model of methane production is proposed that depicts the interaction between hydrogen concentration and methanogens in the rumen. Analytical results show that it meets biological expectations, namely increased fractional passage rate leads to a greater growth rate of methanogens, and a greater steady state hydrogen concentration. This model provides a basis on which to develop a more comprehensive model of methane production in the rumen that includes thermodynamics and feed fermentation pathways.