The estimated nutritive value of three common grassland species at three primary growth harvest dates following ensiling and fractionation of press-cake

Abstract

In a Green Biorefinery processing green biomass one possible application for the press-cake fraction is as a feedstuff for ruminants. This study investigates the effects of ensiling and fractionation on the estimated nutritive value of three grassland species harvested at different stages of maturity. Perennial ryegrass (Lolium perenne L., var. 'Gandalf'), cocksfoot (Dactylis glomerata L., var. 'Pizza') and red clover (Trifolium pratense L., var. 'Merviot',) were grown in field plots and harvested and ensiled in laboratory silos. These silages were subsequently fractionated into presscake and press-juice fractions. Loss of soluble, fermentable organic matter during ensiling increased the relative proportions of fibre and crude protein. Fractionation resulted in the substantial reduction of herbage soluble nutrient and mineral content, increasing the fibre content and reducing digestibility and crude protein. The low energy and protein content of the press-cake fraction, especially at later harvest dates, will limit its use in ruminant diets.