Study On Feeding Value And Feeding Way Of Caragana Fabr.Dominated Desert Shrubs In Arid Area Of Northern China

Desert shrubs are the main ecological plant in sandland or arid area,making its large quantity of resource.If were developed as feed,they can promote achieving both economical and ecological benefits.Nutrient of Caragana micropylla Lam.Caragana korshinskii Kom.,Salix psammophila C.Wang et Chang Y.Yang,Hedysafum laeve Maxim.,Hedysarum scoparium Fisch.et Mey.,and Amorpha fruticosa Linn.,were measured under different treatment.And in vitro dry matter digestibility of several feeds were measured.Based on shrub nutritional character and prices,several shrub-dominated feed formula were designed to carry out feed experiment on sheep in winter,in which sheep weight gains,dry matter intake,feed consumed and cost as well as digestibility were measured,incorporated with principal component analysis were done to screen optimized shrub-dominated feed formula.Conclusion were drawn as follows.1.shrub nutritive value evaluation(1)Caragana korshinskii and Amorpha fruticosa had higher CP content of over 10%.Caragana korshinskii were at the highest level of nutritive value for its nutrient was high and difference between months and up-down proportion of it's stalk were small,that is both spatial and temporal difference were small,Hedysarum laeve and Hedysarum scoparium were on the contrary,for which proportion of high nutritional high part were low.Salix psammophila were low CP,but high in EE and WSC.Caragana korshinskii and Salix psammophila had higher EE content about 7%-8%,higher than others.5 desert shrubs were 35%-50%in ADF and 50%-70%in NDF.Caragana korshinskii and Amorpha fruticosa were in relatively lower level.(2)Caragana microphylla had high CP content about 6.58%-17.29%,exceeding to most grass and corn straw,but its cellulose content were also high,with ADF 50%-60%and NDF 60%-70%.Delicate branch had a higher nutritive value than coarse branch.Stumping helped obtaining more delicate branches.Plant after stumping 1 year had higher nutrient value than 2 year,which higher than plant without stumping.Nutrient value difference were not significant from July to September,while decreased rapidly from September to October.Thus harvesting time should be no later than September.(3)Caragana Fabr.feed product had a higher CP and EE along with a higher ADF and NDF than maize straw.Rubbing,Smashing,and pelletizing helped reducing ADF and NDF.IVDMD has significantly negative correlation with NDF and ADF,and positive correlation with CP.2.Optimizing of desert shrub dominated feed formulaDiet with 70%roughage which contained caragana only could maintain sheep's normal growth.When caragana covered 55%in diet,sheep could gain weight closed to fattening effect.Salix psammophila has a inferior palatability and proportion in formula should not be too high.Digestibility were in direct proportion to weight gain.Several shrub feed in which roughage mainly consists of shrub and concentrate mainly consists of maize meal and soybean meal were screened as optimized feed formula.(1)High input with high output:concentrate covers about 30%;roughage covers about 70%,including Caragana 35%,Salix psammophila 10%and maize straw 25%,(2)Low input with high output:A.concentrate covers about 20%;roughage covers about 80%,including Caragana 55%,Salix psammophila 10%,others are maize straw;B.concentrate covers about 30%;roughage covers about 70%,all of which are Caragana.(3)Sustaining formula with low cost:concentrate covers about 20%;roughage covers about 80%,all of which are shrub feeds,including Caragana 75%and Salix psammophila 25%.