Bacteria of the ovine rumen I. The composition of the population on a diet of poor teff hay

Abstract

1. The composition of the bacterial population in the rumen of adult merino wethers conditioned to a diet of poor teff hay was studied during three consecutive periods of 60, 109 and 42 days when the ration was 1200,600 and 300 g. per day, respectively.2. In all three periods there was no significant difference between the three sheep with regard to either the viable counts of the functional groups of bacteria fermenting cellulose, starch, glucose, xylose and lactate or the percentage proportions of the different morphological types occurring in each group.3. The reduction of food intake had little or no influence on either the numbers or the morphological types of bacteria in each functional group.4. The animals lost weight at approximately the same rate throughout the three periods of the experiment which was ended when they were in a state of prostration.5. These results suggest that, providing the diet is changed only in respect of quantity, important functional groups of rumen bacteria can survive at levels of food intake which are insufficient for the survival of the animal.