SUMMARY: In sheep fed once daily, the concentrations of micro-organisms in the rumen changed with the time after feeding, some organisms fluctuating in numbers more than others; peak concentrations were reached at different times for different organisms. These changes in concentration were reflected in changes in the proportion of dividing cells, for example, in this proportion varied from less than 0.2% throughout most of the day to a maximum of 23 % a few hours before feeding; for spp. the variation was less: it was possible to calculate the minimum doubling time for these latter organisms as about 5 hr.

One animal at different times, or different animals, on the same ration and dietary regime had very different rumen microbial populations, these differences being particularly marked in the case of some organisms. Reasons why these marked differences in microbial population are not reflected in similarly marked differences in over-all rumen metabolism are discussed.

Feeding different quantities of the same ration had little effect on the concentration of rumen microbes, provided the ration was above a minimal level; it is, however, suggested that output of microbial cells from the rumen may have varied with the amount of feed given. Starvation for a few days or prolonged under-nutrition had a marked effect, some organisms being drastically reduced in numbers or dying out completely. When the qualitative nature of the diet was changed, about 10 days were needed to complete the major adjustments in the rumen microbial population.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error