| The alpine meadow on the Qinhai-Tibet Plateau is one of the important pasture in China.The Tibetan sheep is the dominant livestock in this region and is beset with a circle of "fat in summer,strong in autumn,thin in winter,dead in spring " for a long-term,which not only limits the herdsmen income growth,but also aggravates the degradation.The experiments focus on Tibetan sheep’s characteristics of digestion and the metabolism and the forage nutrition seasonal dynamics of the rangeland were conducted in the Maqu county and the main influence factors which affect the interaction of forage and livestock also were analyzed.This study can contribute to analysis the balance of forage supply and livestock demand in this region and also play an important role in economic development and environment protection.The main results are as follows:1.Nutrition of forage is showed as:June is better than August and December.Grass general nutrients,CP content is June>August>December,and the difference among June,August,and December is significant(p<0.05);the contant of ADF and NDF is December the biggest,August next,June minimum,and the difference between June and December is significant(p<0.05),also significant between August and December(p<0.05);but there is no significant difference of NDF contant among June and August and December(p>0.05).Forage crude fat(EE)and ash content(Ash)had no no significant different yearround(p>0.05).The trace elements of grass except Fe accumulated with the growing season,other elements showed:Mn>Zn>Mg>Cu,and gradually reduce with growing season.2.Tibetan sheep digestion and metabolism characteristics:livestock individual average daily feed intake is showed as:August>June>December,and the feed intake reaches the highest in June of 2012,and among June,August and December the different is significant(p<0.05).Average daily gain and relative daily gain is increase in June and August,but reduce in December.The total dung and urine amount are as follows:August>June>December,and the difference is significant(p<0.05),and metabolism of unit weight of waste between June,August and December has no obvious difference(p>0.05).The digestibility reduce with grass growing season,and reach the maximum of 81.5%± 1.46%in June of 2012,and the difference among June,August and December is significant(p<0.05).In the energy of the sheep,digestion and metabolism account for larger proportion,and gradually reduce with grass growing season.Waste energy reach maximum in August of 2012,and manure>urine,and has a significant difference in June,August and December of 2012(p<0.05).3.The grass nutrients content is basically reduced over the growing season,its means that June>August>December.And nutrient elements are in balance within the grazing season,and they can meet the Tibetan sheep’s need.Feces and urine,N and Mg content is urine>dung;but Fe,Mn,Zn,Cu and P is the dung>urine. |
