Voluntary Intake of Dry Matter by African Zebu Cattle

Abstract

Dry matter intake (DMI) in ruminants was reported to be directly related to metabolic body weight (Blaxter, Wainman and Wilson, 1961). However, when steers were fed high energy rations and varied nitrogen (N) intake, it was reported that metabolic body size had no appreciable effect on DMI (Bond et al., 1962). It has been reported that DMI increased with increasing digestible energy intake up to the point where voluntary intake, was no longer limited by gut capacity and then energy demands took over and regulated intake (Montgomery and Baumgardt, 1965). The DMI was found to be inversely related to a rising level of fibre determined as c.:e1!-wall constituents (Colburn, Evans and Ramage, 1968). Gut capacity has been suggested as having an important role in regulation of feed intake (Conrad, 1966). The recurring hunger caused by the rate of passage of digesta out of the ruminoreticulum (Crampton, 1957), the total gut DM content (Blaxter et al., 1961) and the ruminoreticulum fill (Balch and Campling, 1962) have been suggested as playing significant roles in regulation of feed intake in ruminants.