Changes Of Methane Emission In Sheep During Grazing Season In Xilin Gol Typical Steppe

In this study,the study of grazing sheep in Xilinhaote natural grassland was conducted to study the correlation between the changes of nutrient composition and methane yield in different months by the conventional nutrient determination combined with in vitro simulated rumen fermentation technology,and the methane emission from grazing season was studied by the six sulfur fluoride tracer method and the methane emission estimation model.The effect of tea saponin on methane production was studied in vitro.The purpose of this study is to explore the change rule of methane emission in sheep during grazing season.This study is divided into four parts of the test?The study contained four main parts:(1)Determination of vegetative components of grassland dominant speciesThe natural dominant species of pasture were collected from 7,8 and 9 months of grazing season in Xilinhaote grassland,and their nutritional components were determined.The results showed that the changes of nutritional indexes of natural predominant herbage were different in different months.In 8 and September,the content of DM content was higher than that in July,and the difference was significant(P<0.05).The content of NDF and ADL in 8 and September was significantly higher than that in July(P<0.05).In July,the content of CP was the highest in September,and the difference was obvious.(P<0.05).The results showed that the pasture quality of Xilinhaote natural pasture was 7 months,8 months and 9 months,and decreased from month to month.(2)Changes of Methane Yield of Grasses in Grazing SeasonThe effects of volatile fatty acids and dry matter disappearance rate on methane production were measured by in vitro rumen fermentation experiment.The results showed that the total yield of herbage in July was higher than that of 8 and September,but the difference was not significant.The disappearance rate of dry matter in July was higher than that of 8 and September,but the difference was not significant.The difference of volatile fatty acids in pasture was significant(P<0.05).The total yield of herbage,the disappearance rate of dry matter and the monthly decline of volatile fatty acids of herbage made the methane yield change,and the methane production in July was higher than 8 and 9 two months,and the difference was significant(P<0.05).(3)Methane Emission Changes from Sheep in Grazing SeasonThe methane emission from sheep during grazing season was measured by six sulfur sulphur tracer and methane emission estimation model.The results showed that the methane emission in August was 30.86(L/d),and the methane emission was 26.85(L/d)in September,and the methane emission in August was 28.009(L/d).The variation of methane emission measured by the model was similar to that measured by six sulfur fluoride tracer method,and the variation trend of methane production in vitro simulated rumen fermentation test was the same,and decreased month by month.(4)Effect of tea saponin on methane productionIn vitro simulated rumen fermentation test,tea saponin was added to study the effect of tea saponin on methane production.The concentration of tea saponin was set to four gradient concentrations of 0%,0.4%,0.8% and 1.2% of the substrate concentration,and the change of gas yield and methane yield were measured.The results showed that in vitro simulated rumen fermentation test group added tea saponin significantly higher than the control group,(P<0.05),in which the content of tea saponin adding 1.2% was the highest in the in vitro simulated rumen fermentation test.After in vitro culture,the experiment group added tea saponin,the production of methane was more than the control group.The amount of methane decreased significantly(P<0.05),and the yield of methane decreased with the increase of tea saponin concentration.It is concluded that tea saponin has a certain inhibitory effect on methane production in rumen of ruminants.The above results showed that the quality of pasture decreased month by month in the grazing season,and the trend of methane production also showed a downward trend.Tea saponin had a certain inhibitory effect on methane production.