Abstract: The nutrition dynamic variation of forage plays a critical role in improving and regulating the nutritional status of livestock, grass productivity, the development of China's northern grassland animal husbandry. The dry matter (DM), crude ash (Ash), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and the rumen degradability dynamics of Chloris virgata at different growth stages were studied and evaluated in the agro-pastoral zone of Songnen Plain using a nylon bag technique with three Ujumqin sheep fitted with ruminal cannulas. Results showed that the Ash, CP, NDF and ADF contents of Chloris virgate had significant (P<0.05) or highly significant (P<0.01) differences among different growth stages. Both CP and Ash contents decreased, whereas NDF and ADF increased with the maturity progressed. The rapid degradation and effective degradation rate of nutrient components declined with progressive growth stage. The effective degradability of DM was similar to that of OM. The rapid degradation and effective degradation rate of ADF were higher than that of NDF at the same growth stages except withering stage. The comprehensive consideration of nutrient contents and rumen degradation characteristics suggested that Chloris virgata should be harvested during earing to flowering, when had a high nutritional value for animal.

Key words: Chloris virgata, Growth stage, Nutritional components, Rumen degradation rate

摘要： 掌握草地优势牧草营养动态变化规律，对于改善和调控家畜的营养状况，提高草地生产力，发展我国北方草地畜牧业有重要的意义。试验选用3只安装有瘤胃瘘管的乌珠穆沁绵羊（Ujumqin），采用尼龙袋法评定松嫩平原农牧交错区不同生育期虎尾草（Chloris virgata）其干物质（DM）、粗灰分（Ash）、粗蛋白（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）的变化规律及其在瘤胃内的降解特性。结果表明：不同生育期虎尾草的Ash，CP，NDF，ADF含量差异显著（P<0.05）或极显著（P<0.01），Ash和CP含量随着生育期的延长而逐渐降低，NDF和ADF含量则呈逐渐增加趋势；随着生育期的递进，虎尾草各营养成分在绵羊瘤胃内的快速降解组分以及有效降解率呈下降趋势，DM和OM的有效降解率接近，且在同一生育期内（除干枯期外），ADF的快速降解组分和有效降解率均高于NDF。综合考虑虎尾草各生育期所含的营养成分以及在瘤胃内的降解能力，建议虎尾草在抽穗至开花期间进行刈割利用，具有较高的营养价值。

关键词: 虎尾草, 生育期, 营养成分, 瘤胃降解率