[Regulation of microbiologic processes in the rumen of ruminants by bacteriophages of Streptococcus bovis].

Influence of bacteriophages of Streptococcus bovis on microbial activity in the rumen was investigated in experiments on cows. Main elements of the mechanism of bacteriophage action on the microflora have been detected. The daily feeding with bacteriophages results in productive infection of sensitive to them rumen bacteria and is associated with increasing bacteriophage concentration in the rumen contents, lower number and activity of amylolytic bacteria, higher cellolytic activity and increased number of bacteria utilizing xylan, cellobiose and xylose. The fermentation is usually shifted to a higher production of propionate and butyrate at the expense of lower acetate. The regulating action of a single bacteriophage feeding on the rumen microflora and its metabolic activity stops on the fifth day. Daily introduction of bacteriophages into the ration of cows under moderate or high levels of feed increases the milk fat by 0.1-0.3%.