Comparation Of Nutritionnal Value Evaluation Method In Common Roughage For Ruminants

In these series of research, common roughage for ruminants in Northern China were used as testmaterial to study evaluation of the nutrient value for roughage. Cornell net carbohydrate and proteinsystem was used evaluation the carbohydrate and protein fraction, and in situ experiment and in vitrogas production were used evaluation rumen degradation characteristics and in vitro fermentationcharacteristics.And then prediction equations for effective degradability and in vitro digestibility ofnutrients and ermentation parameters were established.The present research included threeexperiments listed as follow.Expriment1: Evaluation of nutrient value in common roughage for ruminant by CNCPSThe objective of this Study was to evaluate the nutrient value of roughage for ruminant in NorthernChina using Cornell net carbohydrate and protein system （CNCPS）, and provide basic feed database forthe application of CNCPS in China.（Method）Total33roughage samples in3classes and7types werecollected from Beijing, Henan, Hebei, Shandong and Inner Mongolia etc.The basic nutrient contentswere analyzed and the carbohydrate and protein fraction were calculated respectively according to theCNCPS method and also did classification analysis.The results showed that the soluble crude protein inroughage is mainly non-protein nitrogen,and true protein content was relatively less. Alfalfa is a kind ofhigh quality roughage with high protein content, low unavailable protein content and high nonstructuralcarbohydrate content The nutrition value of wheat straw is low for the high unavailable fiber and protein.The corn silage feed has higher nutrition value than the straw class feed for the lower content ofunavailable fiber and protein. The nutrition value of waxy maize straw is higher than that of corn stalkand corn stalk silage feed for the higher crude protein and lower unavailable fiber and unavailableprotein.Expriment2: Evaluation of rumen degradation characteristics in common roughage forruminant by in situ experimentThree crossbred Dorper×Thin Tailed Han male sheep fitted with permanent rumen fistula wereselected as samples in the experiment. We evaluated the rumen degradability and effective degradabilityof dry matter （DM）, organic matter （OM） and neutral detergent fiber （NDF） of twenty-seven roughagesby in situ experiment. The results showed that the effective degradability and the degradationparameters of DM, OM and DNF of different kinds of roughage were different. The rumen degradationrate of clover was best, followed by the whole-plant corn silage and corn stalk silage. The rumendegradation rate of Chinese wildrye was worse than the former two kinds and that of wheat straw wasthe worst. The effective degradability of DM, OM and DNF of a kind of roughage had strong positivecorrelation with its nutrient crude protein content, but had strong negative correlation with the contentof neutral detergent fiber and acid detergent fiber. Prediction equations for effective degradability of drymatter using CB₁and CA was PDM（%）=26.9514+1.1362CB₁（%）+0.6495CA（%） R₂0.9057,n=27,P0.0001Also,Prediction equations for effective degradability of organic matter was POM （%）=24.1509+1.1701CB1（%）+0.6906CA（%） R₂0.9266,n=27,P0.0001Prediction equations foreffective degradability of neutral detergent fiber was PNDF（%）=20.9094+0.4874CB1（%）+0.28886CA（%）R₂0.9038,n=27,P0.0001Expriment3: Evaluation of fermentation characteristics in common roughage for ruminants byin vitro gas production.In vitro gas production technique was used to evaluate the in vitro gas production characteristics oftwenty-seven roughages. Difference of fermentation kinetic parameters between different species ofroughage and the relationships between fermentation kinetic parameters and nutrition composition wereanalyzed and discussed. The results showed that in vitro fermentation characteristics were significantlydifferent among different roughage.The the highest and lowest theoretical maximum gas productionwere whole-crop corn silage and alfalfa. The fastest and slowest gas production rate were alfalfa andwheat straw. The longest and shortest fermentation lag time were wheat straw and alfalfa. In vitro drymatter digestibility of alfalfa was the highest,and there were no significant difference between alfalfaand whole-crop corn silage,but there was significant difference between alfalfa and in turn reduce cornstalk silage and Leymus chinensis and corn stalk and wheat straw. Prediction equations for in vitro drymatter digestibility and organic matter digestibility using crude protein and in vitro24h gas productionwere IVDMD（%）=6.0703+0.5652CP（%）+0.8106GP24h（ml/0.2gDM）（R₂=0.9017,n=27,P0.0001） andIVOMD（%）=6.8713+0.4085CP（%）+0.7773GP24h（ml/0.2gDM）（R₂=0.9369,n=27,P0.0001）.Predictionequations for in vitro dry matter digestibility and organic matter digestibility using CA,CB1and PA wereIVDMD（%）=20.2454+0.3862CA（%）+0.7441CB1（%）+0.1164PA（%）（R₂=0.9135,n=27,P0.0001）andIVOMD=20.2534+0.3323CA（%）+0.1240PA（%）+0.6132CB1（%）（R₂=0.9485,n=27,P0.0001）.Prediction equations for NH3-N,TVFA,acetate,propionate and butyrate in using CP,CNSC,CA,CB1,PAwere NH3-N（mg/100ml）=111.9202-0.7489CP（%）+0.2147CNSC（%）（R₂=0.8836,n=27,P0.01）,TVFA（mmol/L）=41.9384+0.5793CB1（%）+0.3788CA（%）+0.2674PA（%） R₂=0.9242,n=27,P0.01,acetate（mmol/L）=26.0598+0.34378CB1（%）+0.2350CA（%）+0.1462PA（%） R₂=0.9228,n=27,P0.0001),propionate（mmol/L）=11.3170+0.0642CB1（%）+0.07528CA（%）+0.0375PA（%）（R₂=0.8219,n=27,P0.0001） and butyrate （mmol/L）=2.7971+0.1682CB1（%）+0.0165CA（%）+0.0493PA（%） R₂=0.9146n=27,P0.0001.