Abstract:

Leymus chinensis, the dominant plant of the northern grassland, is an important forage source of grazing herbivores. The nutritional value of hay has been reported by some studies,but the nutritional value data of Leymus chinensis harvested in different seasons are limited. To evaluate the intake and digestibility of sheep in four seasons, a total of 12 lambs with average body weight of (31.13±2.61) kg were randomly divided into 4 group with 3 replicates per group. The sheep were fed Leymus chinensis hay harvested in spring, summer, autumn, and winter, respectively, with free choice feeding and water. Pre-trial period was 2 weeks and formal trial period was 1 week. The experiment was carried out by total fecal collection. The results showed that seasons had significant effect on DM intake and digestibility. Daily DM intake were 68.30,69.86,57.09 and 32.53 g·kg^-1LW^0.75, and digestibility of DM was 50.75%,50.94%,46.74% and 36.91% in spring, summer, autumn and winter, respectively. The nitrogen balance was negative in autumn and winter, and ingesting Leymus chinensis harvested in winter did not satisfy the requirement of energy and protein for maintaining, therefore,sheep should supplement high-quality legume forages or other protein sources in order to achieve better performance.

Key words: Leymus Chinensis, Intake, Digestibility, Sheep, Season

摘要：

羊草（Leymus chinensis）是北方草地的优势植物，是放牧家畜重要的饲草来源。有关羊草干草营养价值已有相关报道，但关于不同季节刈割的羊草营养价值数据有限。因此本试验选择7月龄乌珠穆沁公羊12只，平均体重为（31.13±2.61）kg，随机分为4个处理，每个处理3个重复。分别饲喂春季、夏季、秋季和冬季末收割的羊草干草，试验绵羊单笼饲养，预饲期2周，试验期1周，自由采食和饮水，采用全收粪法进行消化代谢试验。结果表明，不同季节收割羊草干草对绵羊干物质采食量和消化率有显著的影响（P<0.05），春、夏和秋季采食量和消化率显著高于冬季，春、夏、秋和冬季干物质日采食量分别为68.30，69.86，57.09和32.53 g·kg^-1LW^0.75；干物质消化率分别为50.75%，50.94%，46.74%和36.91%。秋季和冬季氮处于负平衡，冬季枯黄的羊草不能满足绵羊的能量和蛋白质的维持需要，还需要优质豆科牧草或其他蛋白源补充，从而获得更好的生产性能。

关键词: 羊草, 采食量, 消化率, 绵羊, 季节