Variation law of whole-plant corn silage nutritional quality under different storage periods | 全株玉米青贮饲料在贮存期营养品质的变化规律

Chinese. 探讨全株玉米青贮饲料在开窖后营养品质随贮存时间的变化规律，以期更科学地利用青贮饲料。选取生长期为89 d的青玉米秆调制青贮饲料，封窖50 d后开窖取用，考察青贮饲料在50~290 d贮存期间，主要营养物质和发酵产物随时间的变化规律，并对主要营养物质与贮存时间以及纤维类成分与干物质含量之间的相关关系建立一元回归模型。随贮存期的延长，全株玉米青贮的干物质和纤维类物质含量上升(P0.05)，蛋白、淀粉、磷含量均下降(P0.05),钙含量显著下降(P0.05)； pH值和乙酸含量上升(P0.05)，乳酸和丙酸含量下降(P0.05)。青贮饲料中干物质含量与贮存时间成指数相关关系，粗蛋白、淀粉、钙和磷的含量均与贮存时间呈线性相关关系，中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质素均与干物质含量成线性相关关系，其中除磷含量与贮存时间的回归模型外，其余7个模型的拟合效果均较好。全株玉米青贮饲料在贮存期营养品质呈下降趋势；运用数学模型预测青贮饲料营养品质随时间的变化规律是可行的，可为青贮饲料合理利用提供科学依据。

English. In order to ensure the better utilization of silage, the variation law of whole-plant corn silage nutritional quality under different storage periods was studied. The whole-plant corn was harvested and ensiled at the 89th day of growth, and the silo was opened after 50 days fermentation. Main nutrients and fermentation products of whole-plant corn silage at different storage periods from 50 to 290 days were analyzed. The relationship between main nutrients and storage periods was studied and the single-element regression models were built. The results showed that: dry matter and fiber carbohydrate of silage increased (P0.05); crude protein, starch and phosphorus decreased (P0.05), the content of calcium significantly decreased (P0.05). pH and acetic acid were enhanced (P0.05), the content of formic acid and propionic acid reduced (P0.05). The relationship between dry matter and storage periods could be described using an exponential function, and there were linear relations between crude protein, starch, calcium, and phosphorus with storage periods, also the linear relations between acid detergent fiber, neutral detergent fiber, acid detergent lignin with dry matter. Besides the model between phosphorus with storage periods, there was a good fit for the other seven models. The nutritional quality of whole-plant corn silage decreased with different storage periods. It is feasible to forecast the variation law of whole-plant corn silage nutritional quality under different storage periods by the models, and this research achievement can provide scientific basis for the rational utilization of silage.