The effect of haymaking on the neutral detergent soluble fraction of two intercropped forages cut at different growth stages

The aim of the paper was to study the fermentation of the neutral detergent soluble fraction (NDS) using a 2x3x2 factorial arrangement of two intercropped forages (barley/broad bean and vetch/oats) collected at three growth stages and preserved by haymaking. Each feed sample and its isolated NDF were fermented in vitro and gas production was monitored utilizing the in vitro gas production technique (IVGPT). NDS gas yield was determined by the difference between gas from the unfractioned forage and that of its respective NDF. Haymaking decreased gas yield and rate of gas production from the unfractioned forage. Increasing maturity did not change the final gas volume, but reduced the rate of gas production from the NDS fraction. The rate of gas production from the NDS fraction of hay decreased on average by 2.9 ml/h compared with fresh forage. On average, haymaking reduced the gas yield from the NDS fraction by 18.70%. The curve subtraction technique can be used to study the effects of haymaking on the neutral detergent soluble fraction of forages.