Factors affecting the voluntary intake of food by cows

Abstract

The relationship between the voluntary intake of roughage by cattle and the rate of disappearance of digesta from the reticule-rumen was considered earlier (Campling, Freer & Balch, 1961, 1962). It was shown that the voluntary intake, by cows, of hay, oat straw or oat straw with urea was directly related to the rate at which digesta disappeared from the reticulo-rumen by digestion and absorption and by the onward passage of food residues. These findings have led us to investigate some of the factors that affect the passage of food residues from the reticulo-rumen, which include (a) the mean time of retention of food particles in the reticulo-rumen, and (b) the rate of flow of digesta from the reticulo-rumen to the omasum. Rate of passage, as measured by the mean retention time, and the rate of flow were defined by Balch (1961). The interrelationship of these two factors and the extent to which one can vary independently of the other have not previously been explored.