Quantitative determination of methanogenic bacteria in the feces of different mammals

In this research on fresh human, cattle, swine, and rabbit feces, methanogenic bacteria were found in all samples examined, at the following concentrations per gram dry weight: swine, 108; human, 107; cattle, 106; and rabbit, 104. Anaerobic heterotrophic bacteria were found in the following concentrations per gram dry weight: human, 1011; swine, 1011; cattle, 1011; and rabbit, 1010. The total number of O2-intolerant was higher than that of O2-tolerant bacteria: about 10–100 times for methanogenic and 100–1000 times for anaerobic heterotrophic bacteria.