# Concentration of bacteria in rumen

Range | ~1e+10 cells/ml |
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Organism | Sheep Ovis aries |

Reference | Brock TD. Microbial growth rates in nature. Bacteriol Rev. 1971 Mar35(1):39-58. p.52 right column bottom paragraphPubMed ID4929658 |

Method | "The chemostat is an excellent laboratory model of a steady-state population (ref 5), and it is instructive to consider how one measures growth rate in a chemostat, the principles developed there being readily adapted to natural situations. Measurement of growth rate requires a knowledge of the volume of the system (v) and its flow rate (f). The turnover time is v/f and the doubling time is equal to the turnover time." |

Comments | “If [researchers] know the turnover time (flow rate), and [they] know that the microbial population is in steady state, [they] know the doubling time of the population. To calculate the productivity of the population, that is, the number of new cells produced per day, [they] must also know the absolute population size, which can be determined by direct microscopic count. In the sheep rumen, there are about 10^10 bacteria per ml and since the average volume of the sheep rumen is 5 liters, the total population is about 5x10^13 bacteria. If the turnover time were 24 hr, 5X10^13 bacteria would be produced per day.” |

Entered by | Uri M |

ID | 102396 |