内蒙古乌拉盖天然草原不同放牧区混合牧草营养成分和瘤胃发酵特性的研究

Study on the nutrient composition and rumen fermentation characteristics of mixed grass in different grazing areas of Wulagai natural grassland in Inner Mongolia

【目的】评价内蒙古乌拉盖天然草原不同放牧区混合优势牧草营养价值,确定放牧家畜营养供给和最佳放牧区。【方法】测定和分析内蒙古乌拉盖天然草原8个主要放牧区青草期混合优势牧草营养成分、结构性碳水化合物、体外瘤胃发酵特性,并对其营养价值进行综合评定。【结果】乌兰察布嘎查放牧区混合牧草粗蛋白(CP)含量显著低于其他放牧区(P<0.05),乌拉盖水库放牧区混合牧草粗灰分(Ash)含量显著高于其他放牧区(P<0.05),乌兰察布嘎查放牧区和斯仁音昭村放牧区混合牧草钙(Ca)和磷(P)含量显著高于其他放牧区(P<0.05),而宝克牧场放牧区混合牧草可溶性碳水化合物(WSC)含量最高(P<0.05);乌兰察布嘎查放牧区混合牧草酸性洗涤纤维(ADF)、纤维素含量显著高于其他放牧区(P<0.05),查干哈达村放牧区混合牧草中性洗涤纤维(NDF)、酸性洗涤木质素(ADL)、半纤维含量显著低于其他放牧区(P<0.05);瘤胃体外发酵12~48 h,发酵液pH无明显变化,查干哈达村放牧区混合牧草产气量(GP)、体外干物质降解率(DMD)和体外中性洗涤纤维降解率(NDFD)随时间增加呈现递增趋势,均显著高于其他放牧区(P<0.05)。【结论】内蒙古乌拉盖天然草原查干哈达村放牧区混合牧草营养价值最佳。

【Objective】The purpose of the experiment is to evaluate the nutritional value of mixed dominant forages in different grazing areas of Wulagai natural grassland in Inner Mongolia in order to determine the nutritional supply of grazing livestock and the best grazing area.【Method】The nutrient composition,structural carbohydrate and in vitro rumen fermentation characteristics of mixed dominant grass in 8 main grazing areas were measured and analyzed to comprehensively evaluate its nutritional value.【Result】The results showed that crude protein(CP)of mixed herbage in UlanchabuGacha grazing area was significantly lower than that in other grazing areas(P<0.05).The Crude ash(Ash)content of mixed grass in Wulagai reservoir grazing area was significantly higher than that in other grazing areas(P<0.05).The contents of calcium(Ca)and phosphorus(P)in the mixed grass of Wulanchab grazing area and Sirenyinzhao grazing area were significantly higher than those in other grazing areas(P<0.05).The water soluble carbohydrate(WSC)content of mixed grass in Baoke pasture was the highest(P<0.05).Acid detergent fiber(ADF)and cellulose content of mixed grass in UlanchabuGacha grazing area were significantly higher than those in other grazing areas(P<0.05).The content of neutral detergent fiber(NDF),acid detergent lignin(ADL)and hemicellulose of mixed grass in ChaganHada village grazing area were significantly lower than those in other grazing areas(P<0.05).According to rumen fermentation test analysis in vitro,from 12 h to 48 h,pH of fermentation liquid did not change significantly.Gas production(GP),in vitro dry matter degradation(DMD)rate and in vitro neutral detergent fiber degradation(NDFD)rate of mixed herbage in ChaganHada village grazing area increased with time,and were significantly higher than those of other grazing areas(P<0.05).【Conclusion】Comprehensive analysis shows that the nutritional value of mixed herbage in ChaganHada village of Wulagai natural grassland is the best,the results can provide data reference for accurate balance of nutrient supply of grazing livestock and efficient transformation of natural herbage in cattle and sheep grassland production system.