Abstract: It is important to understand the dynamics of feeding value of forage in different seasons,which is of great significance for improving and regulating the nutritional status of livestock. Chloris virgata is an important forage for grazing livestock as a dominant forage with good drought and salinization tolerance in Songnen grassland. However,the current data on the feeding value of Chloris virgata is limited. Therefore,to evaluate the intake and digestibility of Chloris virgata in four seasons,twelve Ujimqin sheep (27.37±2.20 kg body weight;all rams) were randomly divided into four groups with three replicates per group. The sheep were fed Chloris virgata in spring,summer,autumn and winter respectively,with free choice feeding and clean water. The experiment was carried out by total fecal collection. The results showed that the dry matter intake of the grass of spring,summer,autumn and winter per kilogram of metabolic weight were 73.48,30.01,29.80 and 34.33 g·kg^-1 LW^0.75,respectively,and the spring was significantly higher than other seasons (P<0.05). The Chloris virgata in different seasons had significant effects on the dry matter digestibility,neutral detergent fiber digestibility,carbon and nitrogen intake,and excretion in sheep (P<0.05) with the highest in spring. The nitrogen balance in spring was positive,so the nitrogen intake in spring could meet the need to maintain part of the weight gain.

Key words: Chloris virgata, Sheep, Intake, Digestibility, Season

摘要： 研究不同季节草地牧草的饲喂价值动态变化规律，对于改善和调控家畜的营养状况具有重要的意义。虎尾草（Chloris virgata）作为松嫩草地一种耐旱、耐盐碱的优势饲草，是放牧家畜重要的饲草来源。但目前有关虎尾草的饲喂价值数据有限。因此，本试验选择乌珠穆沁公羊12只，平均体重为27.37±2.20 kg，随机分为4个处理，每个处理3个重复。分别饲喂春、夏、秋、冬四季的虎尾草干草，试验绵羊采取单笼饲养，采用全收粪法进行消化代谢试验。结果表明，春、夏、秋、冬四季绵羊每公斤代谢体重虎尾草干物质采食量分别为73.48，30.01，29.80和34.33 g·kg^-1LW^0.75，春季显著高于其他季节（P<0.05）；不同季节的虎尾草对绵羊干物质消化率、中性洗涤纤维消化率、以及碳、氮采食和排泄均有显著影响（P<0.05），表现为春季最高，并且春季氮代谢处于正平衡，氮的摄入量可以满足部分增重的需要。

关键词: 虎尾草, 绵羊, 采食量, 消化率, 季节