Efficiency of food conversion
In this CAL the important issue in regard to food conversion efficiency relates to the production of propionate in the reticulo-rumen, the factors that affect it, and the utilization of propionate in the liver of the host ruminant. First you must remember that methanogens alter the pattern of fermentation of some organisms with which they live in syntrophic relationships so as to reduce succinate production. Succinate is a substrate for production of propionate in some other microorganisms. Propionate is an important gluconeogenic substrate in the liver of the host.  This means that a reduction in propionate production places increased demands on the use of amino acids for gluconeogenesis in the host liver and kidney cortex. This reduces the availability of amino acids for protein production in host tissues such as muscle.  From this it is clear that abundant growth of methanogens in the reticulo-rumen causes reduced food conversion efficiency in the host.  The effect can be clearly demonstrated in controlled feeding trials and is one of the reasons for Agribusiness interest in Methanogenesis.