The Effects Of Alpine Meadow Native Grass And Cultivated Oats On Digestion And Metabolism Of Tibetan Sheep

The feeding value of forage is one of the important indexes to evaluate the quality of pasture.Through the experiment of livestock feeding,reveal that the digestive and metabolic mechanism of native grass and oat can provide theoretical basis for the seasonal supplementary feeding of livestock in the alpine pastoral area,which is of great significance to protect the grassland resources and solve the unbalanced of grass and livestock.In this study,we used the typical alpine meadow native grass and artificial cultivated oat in Maqu county,Gansu province,as the main research objects,and the digestion and metabolism experiments of Tibetan sheep were carried out.The experiment was carried out by setting up different grass feeding experiments,qualitative and quantitative analysis digestibility,nitrogen balance and nitrogen use efficiency,energy use efficiency and methane emissions when feeding different grass in different seasons.The results of the study are as follows:(1)In the summer,the water content of oat was significantly higher than that of native grass(P<0.001),there was no significant difference between two groups in winter(P>0.05).Oat CP,WSC,DE and ME content were significantly higher than those of native grass(P<0.05)in both summer and winter,while native grass NDF and ADF content were significantly higher than those of oat(P<0.05).This indicates that the palatability of oat grass is superior to that of native grass whether in summer or winter.There was no significant difference in the gross energy(GE)contents of oat and native grass in both summer and winter(P>0.05).(2)Digestibility results showed that: In summer,the digestibility of oat nutrient was significantly higher than that of native grass(P<0.001),and the digestibility was up to 80%.There were no significant differences in DM and OM digestibility between the two grass(P>0.05)in winter,but had the tendency of oat was higher than that of native grass,and the digestibility of oat DM was more than 60%.However,NDF and ADF digestibility were native grass significantly higher than those of oat(P<0.05),which may be due to the decrease of native grass quality and the sharp increase of NDF and ADF contents with the change of seasons,result in NDF and ADF ingestion of Tibetan sheep increase.Oat CP and EE digestibility were significantly higher than that of native grass in winter(P<0.001).The digestibility of nutrients for oat and native grass was significantly higher in summer than in winter(P<0.001).(3)In the maintained state,Tibetan sheep intake the same level of oat and native grass,total nitrogen intake,digestible nitrogen,nitrogen deposition and nitrogen deposition rate in forages were significantly different in both summer and winter.Tibetan sheep either in summer or winter,feeding oat total nitrogen intake,digestible nitrogen,nitrogen deposition and nitrogen deposition rate were significantly higher than that of native grass(P<0.001),and the nitrogen deposition of native grass was negative in winter.Tibetan sheep intake oat and native grass digestible nitrogen,nitrogen deposition and nitrogen deposition rate were increased linearly with the increase of total nitrogen ingestion,and the growth rate of oat was higher than that of native grass.The relationship between nitrogen deposition and digestible nitrogen showed the same result.These results indicated that the utilization efficiency of nitrogen in the oat was significantly higher than that of native grass.(4)Whether in summer or winter,Tibetan sheep feeding two grass always the same situation in gross energy intake(GEI),but the digestible energy(DE),metabolizable energy(ME),DE/GEI and ME/GEI of oat were significantly higher than those of native grass(P<0.001),and the summer was higher than that in winter(P<0.001).Tibetan sheep intake oat and native grass methane emissions were also significant differences,show the native grass significantly higher than that of oat(P<0.001),winter significantly higher than the summer(P>0.001).total energy use results showed that the Tibetan sheep intake oat and native grass DE/GEI and ME/GEI were increased linearly with the increase of gross energy intake,and increase rate of oat both were higher than the native grass;the ratio of faecal energy(FE)and gross energy intake decreased linearly with the increase of gross energy intake,and the ruduce rate of oat were higher than that of native grass.In summary,both in summer and winter,the nutritional quality and feeding value of oat were significantly higher than that of native grass.In the summer mowing can be made into the silage to preserve its nutritional value for winter livestock feeding use,autumn mowing can be made oat hay to increase the yield,expand the source of winter forage.