关键词: 全株玉米青贮, 乳酸菌, 发酵品质, 营养价值, 瘤胃降解率

Abstract: This experiment was conducted to evaluate the effects of lactic acid bacteria (LAB) inoculant level and fermentation time on nutritional value and fermentation quality of whole-crop maize silage. Maize variety Deng Hai 605 was chosen for the research. The crop was harvested at the 2/3 milk line development stage and four treatments (0, 10, 20 and 30 mg·kg^-1 of LAB preparation added) with four replicates were set up. Samples were ensiled for 45 or 90 days and then analyzed for nutrient composition, fermentation quality and ruminal degradability. It was found that the dry matter (DM) content was not affected by LAB inoculant level and fermentation time (P>0.05). With increase in LAB addition, the neutral detergent fiber (NDF) content of silage fermented for 90 days linearly decreased (P=0.018), while the relative feeding value (RFV) linearly increased (P=0.006). The acid detergent fiber (ADF) content and pH value after 90 days of fermentation were lower than that after 45 days of fermentation (P<0.01), while the content of lactic acid and acetic acid were higher at 90 days than after 45 days of fermentation (P<0.05). The content of lactic increased linearly with increase in LAB (P<0.05). The 24 h ruminal degradability of DM and NDF were unaffected by LAB addition level and fermentation time (P>0.05). With increase in LAB, the 48 h ruminal degradability of silage fermented 90 days linearly increased (P=0.034). The 48 h ruminal degradability of NDF of silage fermented 90 days was higher than that ensiled for 45 days (P=0.022). The RFV, total digestible nutrients and organic acid content were highest and the pH value was lowest in the 20 mg·kg^-1 group after 90 days of fermentation. In conclusion, the whole-crop maize silage with 20 mg·kg^-1 LAB preparation added, and fermented 90 days, had the optimal nutritional value and fermentation quality.

Key words: whole corn silage, lactic acid bacteria, fermentation quality, nutritional value, ruminal degradability