| The purpose of this study was to investigate the nutrients concentration,ruminal degradability,in vitro fermentation,and their correlation of 4 types of common feedstuffs for beef cattle in Jilin Province.Cornell net carbohydrate and protein system?CNCPS?,in situ and in vitro techniques were used to carry out this experiment.The present research included three experiments.Expriment 1:Using CNCPS system to evaluate the nutritional value of feedstuffs for beef cattle in Jilin ProvinceFour types of feedstuffs for beef cattle used in this experiment.The corn silage?emulsification period??alfalfa?Gongnong No.1,mature period?and wheat bran were collected from The Branch Academy of Animal Science,Jilin Academy of Agricultural Sciences,Gongzhuling,Jilin Province.The leymus chinensis was collected from the Shuangcheng of Jilin Province.The nutrients concentration of feedstuffs was analyzed and the carbohydrate and protein fraction were calculated respectively according to the CNCPS method and also did classification analysis.The result showed,in the carbohydrate fractions,CC?%carbohydrate?concentration from high to low were alfalfa,leymus chinensis,corn silage and wheat bran,indicating that carbohydrate availability of wheat bran was the highest.The concentration of CNSC?%carbohydrate?and CA in alfalfa was higher than leymus chinensis.Therefore,Alfalfa degraded rapidly in rumen and was a kind of roughage providing higher quality carbohydrate.The analysis of CP fraction result showed that the highest availability of CP was wheat bran.And the availability of CP from high to low were corn silage,alfalfa and leymus chinensis.Expriment 2:Evaluation of ruminal degradatibility of feedstuffs for beef cattle in Jilin Province by in situ methodThree Chinese grassland Red Bulls,the same weight?BW?of 500±18 kg,with permanent rumen fistula,were used as experimental animals.In situ method was used to test nutrients degradatibility of four feedstuffs in rumen at different time.The rumen degradation parameters and effective degradatibility were also calculated and analyzed.The results showed that the nutrients degradatibility would rise with extending stay in rumen.The DM,OM,CP and NDF effective degradatibility of three roughages were loewr than wheat bran?P<0.05?.Prediction equations for effective degradability of DM,OM,CP and NDF and CB1,CA and PC were PDM?%?=86.563-0.5913CB2?R2=0.9852?;PNDF?%?=46.565+0.4305CA?R2=0.9240?;POM?%?=89.054-3.3486 PC?R2=0.9956?;PCP?%?=64.494+0.5418CA?R2=0.9454?;PCP?%?=83.477-1.5549 PC?R2=1??Expriment 3:Evaluation of fermentation characteristics in four feedstuffs for beef cattle in Jilin Province by in vitro gas production techniqueIn vitro gas production technique was used to evaluate fermentation characteristics of four feedstuffs.In vitro gas production at 2h,6h,12h and 24h,and pH,NH3-N and VFA of cultivated fluid after 24h in vitro fermentation were tested.The results showed that gas production of wheat bran was significantly higher than others?P<0.05?.In vitro DM digestibility?IVDMD?of wheat bran was significantly higher than others?P<0.05?,and the DM and OM digestibility followed this order,wheat bran>Alfalfa>corn silage>Leymus chinensis.There was no significant difference between corn silage and Alfalfa on in vitro DM digestibility.The in vitro DM degradability and in vitro OM degradability?IVOMD?were significantly posstively correlated with the 24h in vitro gas production(GP24)?P<0.05?.The DM effective degradability was significantly posstively correlated with the 24h in vitro DM and OM degradatibility?P<0.05?.The NDF effective degradability was significantly posstively correlated with the 24h in vitro CP degradatibility?P<0.05?.The prediction equations for IVDMD,IVOMD,PDM and PNDF were IVDMD?%?=0.4228GP24+14.194?R2=0.9039?;IVOMD?%?=0.4472GP24?mg/m3?+11.152?R2=0.9337?;PDM?%?=0.436IVDMD+39.949?R2=0.995??PDM?%?=0.422IVOMD+41.227?R2=1?;PNDF?%?=0.42IVCPD+24.24?R2=0.931??... |
PDF Full Text Request