Effects of wilting and mechanical conditioning on proteolysis in sainfoin ( Onobrychis viciifolia Scop) wilted herbage and silage

Ensiling legumes allows conservation of high‐quality forage. However, severe protein degradation occurs during ensiling of legumes. A field study was carried out in 1999 on sainfoin ( Onobrychis viciifolia Scop) to investigate the effects of wilting and mechanical conditioning on proteolysis in wilted herbage and silage. The herbage was cut with both a rubber roll conditioning machine (C) and with a mower without conditioner (U). It was wilted in the field to three dry matter (DM) levels (220, 330 and 440 g kg −1 ) and ensiled in laboratory glass silos. The herbages and the silages were analysed for ensilability characteristics, fermentation quality and nitrogen fractions. During wilting the non‐protein nitrogen (NPN) values increased ( p < 0.05) in both U and C treatment. The free amino acid (free AA) values increased ( p < 0.05) from 2.4 to 12.9 and from 2.4 to 7.2 mol kg −1 total nitrogen, in the U and C treatments, respectively. Low wilted silages (DM content <320 g kg −1 ) underwent butyric acid fermentation and extensive proteolysis in both treatments, with lower ( p < 0.05) NPN and free AA values in the C treatment. Mechanical conditioning may limit protein breakdown and catabolism of some essential amino acids by reducing the field wilting time in both sainfoin wilted herbage and silage. Copyright © 2004 Society of Chemical Industry