Abstract:

This research explored the ideal harvesting time and feasibility of ensilage of native grass in the Hulun Buir region. Native grass was harvested on July 11 （T₁ group）， July 16 （T₂ group）， July 21 （T₃ group）， July 26 （T₄ group）， and July 31 （T₅ group） in 2022. The harvested native grass was processed by natural drying， ensiling with fermentation， or artificial drying. The fermentation quality， nutritional quality， and in vitro digestibility of the products were evaluated. It was found that the fermentation quality of silage prepared from native grass harvested at the five different times was good. Compared with the other groups， the T₃ and T₄ groups of native grass silage had the highest levels of lactic acid （LA） and acetic acid （AA）， and lower pH values and NH₃-N/TN. Compared with their corresponding naturally dried groups， the silage made from the T₂， T₃， T₄， and T₅ groups showed significantly higher crude protein （CP） content （P<0.05）， significantly lower soluble water-soluble carbohydrate （P<0.05）， and no significant difference in neutral detergent fiber （NDF） and acid detergent fiber （ADF） contents （P>0.05）. The in vitro digestibility of dry matter （IVDMD） and crude protein （IVCPD） of native grass significantly increased with later harvest times （P<0.05）. In the silage fermentation， natural drying， and artificial drying treatments， the T₄ group of harvested native grass had the highest CP content， lower NDF and ADF contents， and higher IVDMD and IVCPD. The nutritional quality and in vitro digestibility of native grass silage were higher than those of naturally dried and artificially dried native grass. The quality of silage prepared from native grass harvested on July 26^th was the best. Therefore， it is recommended to harvest native grass for ensiling in mid- to late July.

Key words: harvest period, native grass, natural drying, silage fermentation, in vitro digestibility rate