试验选用5只瘤胃瘘管羊,用尼龙袋法对采自甘肃玛曲高寒草甸、沼泽化草甸、甘肃张掖平山湖荒漠草原及新疆温性草原天然混合牧草的干物质消化率(DMD)和营养成分进行测定.结果表明,高海拔地区的高寒草甸和沼泽化草甸牧草干物质消化率显著高于低海拔地区荒漠草原,且随着时间的推移,高寒草甸和沼泽化草甸牧草干物质消化率先升高后降低,且在6月体内消化率达到最高,而平山湖荒漠草原表现相反趋势.新疆温性荒漠草原则随着季节的变化,从花期-果期-枯草期牧草干物质消化率逐渐降低.玛曲高寒草甸牧草干物质消化率与牧草粗蛋白含量(CP)呈极显著正相关(P〈0.01),与牧草中酸性洗涤纤维(ADF),中性洗涤纤维(NDF)呈极显著负相关(P〈0.01);牧草生育期与CP含量和DMD 呈极显著负相关,与DM,ADF,NDF 均呈极显著正相关(P〈0.01),说明在高寒牧区,6,7和8月牧草营养价值较高,可满足放牧家畜维持和生产能量需要.
The digestibility of dry matter in forages collected from Maqu alpine meadow,swampy meadow, Pingshan lake desert steppe of Zhangye in Gansu and temperate steppe in Xinjiang was analyzed using the nylon bag method in 5 rumen-fistulated sheep.The digestibility of forage dry matter in alpine meadow and swampy meadow in high altitude areas was significantly higher than that of herbage from desert steppe of low altitude areas.In addition,the digestibility of forage dry matter in alpine meadow and swampy meadow tended to rise in spring to a peak in June and then decline in late season,while the opposite trend was observed in Pingshanlake desert steppe of Zhangye.In contrast,the digestibility of forage dry matter in Xinjiang temperate steppe exhibited a declining trend as herbage progressed through flowering,seed set,and hay stages of growth.As expected,forage dry matter digestibility was significantly positively correlated (P <0.01 )with forage crude protein (CP)content,and significantly negatively correlated (P <0.01)with ADF and NDF in alpine meadow. That is,forage growth stage was negatively correlated with CP content and DMD,but was highly positively correlated with DM,ADF,and NDF (P <0.01 ).The study indicated that the forage from alpine meadow in June,July and August had very high nutritional content,and is ideal to meet the energy needs of maintenance and growth,for grazing livestock.