Utilization of Lolium multiflorum by sheep 1. Influence of dry matter content and correlated factors on voluntary intake

Abstract

The intake by young sheep of Lolium multiflorum cv. Midmar (ryegrass) with dry matter (DM) contents of between 10.2% and 20.5% was studied. Intake was measured on pasture, while at the same time herbage was cut and fed either fresh or dry indoors. Additional variables were sward height at pasture and chop length indoors. Quality parameters did not change much between DM contents studied. Intake of wet herbage remained fairly constant irrespective of DM content, suggesting that moisture levels exert a controlling influence on intake. Organic matter (OM) intake increased dramatically with DM content, from 47.4 to 87.4 g kg⁻¹ W^0.75 day⁻¹. Sward height did not influence OM intake significantly, but chop length of cut herbage did. At low DM content the long chop length depressed intake, possibly because of increased chewing and rumination times, while no effect was observed at higher DM contents. It was concluded that if the intake of Midmar ryegrass is to be maximized the DM content of pasture should be at least 18–20%.