| Two experiments were carried out to investigate the effects of adding wheat bran(WB) or beet pulp(BP) on fermentation and nutritive value of silages from high moisture ryegrass(Expt. 1),and to study the effects of wilting on silage fermentation and nutritive value(Expt.2).In Expt.l,high moisture ryegrass was ensiled with WB or BP at four adding levels:0,40,80 and 120g/kg(fresh basis),respectively. All above silages were prepared triplicate in laboratory scale silos and opened 40 days after ensilage. The fermentation characteristics were evaluated by subjective quality,chemical composition,organic acids and pH value. The digestibility of energy and protein of ryegrass silage were predicted in vitro.Addition of WB or BP improved the fermentation characteristics and nutritive value of ryegrass silages. Compared to the control,the ratio of ammonia nitrogen to the total (NH3-N/TN) was decreased by 38.3,47.4 and 45.9%(p<0.01),the pH value was decreased by 3.2,9.9 and 7.1%(p<0.01),when ryegrass was added at levels of 4,8 and 12% WB. In BP added silages,the (NH3-N/TN) value was 40.8,44.4 and 51.5%(p<0.01) lower,the pH value was 0.69,6.4 and 7.3%(p<0.01) lower in groups 1,2 and 3 than those in control,respectively.The dry matter recovery(DMR) was 0.7,3.5 and 3.9%(p<0.05) higher,and the crude protein recovery(CPR) was 2.0,4.3 and 4.7%(p<0.05) higher for the WB-added silages than the control. Compared to the control,the DMR was increased by 6.2,5.4 and6.5%(p<0.01) and the CPR was increased by 7.1,7.1 and 7.8%(p<0.01) for the BP-added silage.Addition of WB or BP increased total organic acid content of silages,significantly decreased the content of propionic acid (p<0.01) and butyric acid (p<0.01). There were no butyric acids found in the silages added with higher levels of WB or BP. The lactic acid content was 76.5,140.8 and 119.7%(p<0.01) higher in WB-added groups than that in control. Compared to the control,the lactic acid content was increased by 0.9,44.7 and 60.2%(p<0.05) in BP-added groups. However there were little differences in acetate content between the groups treated with WB or BP.The in vitro crude protein digestibility (IVCPD) were all significantly higher in WB or BP-added groups than that in the control. The IVCPD in WB-added silage was 74. 76 and 77%(p<0.01) higher than that in the control. Addition of BP significantly increased the IVCPD,which was 52.7,56.1 and 74%(p<0.01) higher than the control group,respectively. The digestible energy (DE) and DM fermentation ratio (DMFR) showed no significant differences in BP-added silages. However the DE was 11.4,26.6 and 34.2%(p<0.01) higher for the WB-added silages than the control.In Expt.2,the effects of wilting prior to ensiling on fermentation characteristics and nutritive value were studied. The DM content of ryegrass was increased by wilting from 118g/kg (control) to 154 and 325g/kg,respectively. All above materials were prepared triplicate in laboratory scale silos and opened 40 days after ensilage. Wilting generally decreased water at bottom of silos,implying less effluent on farm from silo. Compared to the control,the DMR was 2.9 and 6.8%(p<0.01) higher,and the NH3-N/TN value was 12.2 and 19.4%(p<0.01) lower for the wilted silages,respectively. The pH and contents of lactic,acetic and total acids showed no significant differences between the groups (p>0.05). The contents of propionic and butyric acid were significantly decreased(p<0.01). The DE and DMFR also showed no significant differences between the groups,while wilting significantly increased the IVCPD value,which was increased by 32.6 and 42.3%(p<0.01),respectively.In summary,it is difficult to ensile fresh ryegrass successfully without any additive. Addition of WB or BP may reduce dry matter losses during ensilage,andimprove both the fermentation quality and nutritional value of ryegrass silages. The more the adding level of WB or BP,the better the effect on the fermentation quality of ryegrass silages. The optimal level at which wheat bran or beet pulp is added will de...
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