The Development of Calves Raised without Protozoa and Certain other Characteristic Rumen Microorganisms

Abstract

Three Jersey calves, which were raised in segregation to 6 months of age on rations of alfalfa hay (free choice) and grain in quantities equal to half the hay eaten, had rumens devoid of usual rumen microfauna and certain characteristic microflora being used as indicators of the presence of usual rumen microorganisms. Although avg. gains in weight were almost equal to those of rumen-inoculated control calves, their haircoats were rough and their abdomens appeared abnormally deep and pot-bellied. A 4th calf, which received a partial rumen inoculation that resulted in establishment of a large, cigar-shaped indicator microorganism but none of the usual microfauna, resembled in appearance the inoculated calves. The 3 calves had a persistent habit of nosing down through the bedding to pick up wet bits of straw, considered possibly due to a stimulus to seek substitute rumen microorganisms.