The Influence of Casein upon Roughage Digestion in Cattle with Rumen Bacteriological Studies

Abstract

Various additions of casein to a low-protein cattle ration containing roughage and corn starch resulted in increased dry matter digestibility of the roughage part of the ration. Rumen bacteriological studies with and without the casein additions revealed differences which correlated closely with the degree of roughage digestion. These studies included counts of the rumen bacterial populations, Gram stain morphology observations, and cultural work pertaining to the physiology of the rumen bacteria present. The results offer further evidence of the need for a minimum protein requirement for efficient roughage digestion in cattle, especially when starch or starchy grains make up a part of the ration. This minimum protein requirement is interpreted as representing a protein (nitrogen) requirement for the growth of rumen micro-organisms directly involved in roughage digestion.