Development of Rumen Function in the Dairy Calf. II. Effect of Diet upon Characteristics of the Rumen Flora and Fauna of Young Calves

Abstract

When calves received solid feeds, the general pattern of rumen function development seemed to be a sharp fall in the aerobic bacteria within the first 3 weeks, an increase in the total numbers of bacteria, and the establishment of. protozoa. Rumen acids were at adult levels by 6 weeks of age; whereas, the protozoal and bacterial numbers approached this point a little later. The establishment of adult-type organisms and cellulose digestion were slowest to develop and were hindered by aureomycin and liberal milk feeding. Biotin, niacin, and riboflavin levels increased up to 7 weeks of age, with an indication of synthesis early in life.