10^4 - 10^6 cells/ml
||Matthews et al., The rumen microbiome: a crucial consideration when optimising milk and meat production and nitrogen utilisation efficiency, Gut Microbes. 2019 10(2):115-132.
doi: 10.1080/19490976.2018.1505176 p.119 left column 2nd paragraphPubMed ID30207838
||McSweeney CS, Mackie R. Micro-organisms and ruminant digestion: state of knowledge, trends and future prospects. 2012.
||P.119 left column 2nd paragraph: "Ciliate protozoa are found in the range of 10^4 – 10^6 cells/ml in rumen fluid and are responsible for 30 to 40% of overall fibre digestion (primary source)."
||Ron Milo - Admin