Bacteria of the ovine rumen IV. Effect of change of diet on the predominant type of cellulose-digesting bacteria

Abstract

It has been repeatedly shown that bacterial populations of different composition become established in the rumen of animals conditioned to different diets (Bryant & Burkey, 1953; Maki & Foster, 1957; Hungate, 1957; Warner, 1962). On changing ruminants from one diet to another, a reproducible physiological response of the animal to the new diet is often obtained only after a lapse of some weeks. This has been attributed to fluctuations in the levels of different groups of bacteria participating in the digestion of the ration before a new equilibrium between the species is attained. However, little is known about the rate at which these changes occur, mainly because the counting methods for specific bacteria which depend upon the isolation and cultural identification of the organisms are too laborious and time-consuming for examining samples of rumen contents at short intervals after a change of diet.