Estimation Of Total Tract Apparent Digestibility Of Nutrients In Beef Diets Using CNCPS

The objective of the experiments was to study the possibility of using CNCPS to predict the nutrient digestibility of rations for ox.Trai 1:Determination the conventional diet composition and CNCPS components of eight rations.Trial 2:The digestion trial was carried out using fore adult ox. Three rations were allocated to the ox in four 3x4 incompletely Latin square design. Each period lasted 18 days, of which the first 15 days were for adaptation and the last 3 days were for sample collection. The in vivo digestibilities of DM, OM, CP.ADF and ADF of the rations were determined.Trial 3:In vivo digestibility of feedstuffs was predicted using CNCPS contents. The results showed that there were highly relationship between CNCPS contents (%/DM) and in vivo digestibility (Y,%) of DM, OM and CP. The correlation equations were showed as following:DM:Y= 52.91+0.89PA+3.36PB1+0.01 PB2+1.57 PB3+2.91PC (n=12, R2= 0.95, P <0.01); Y= 15.90+0.08CA+2.12CB1+0.28 CB2- 0.53CC (n= 12, R2= 0.90, P<0.01);OM:Y= 56.15-1.27PA-1.04 PB1+1.62 PB2+1.53 PB3+3.27PC (n=12, R2= 0.90, P <0.011 Y=77.06-0.67CA+3.24CB1-1.49CB2-2.15CC (n=12, R2= 0.82, P<0.01)CP:Y= 20.00-10.92PA+1.08 PB1-6.78 PB2-9.18 PB3-3.82PC (n= 12, R2= 0.88, P<0.011The digestibilities of DM and OM could be predicted by CNCPS contents. The digestibility of CP could be predicted by protein contents. There was highly relationship between the digestibiligty of ADF (Y,%) and protein contents (%/DM), the correlation equation was Y= 22.67-1.42PA+0.72 PB1+7.91 PB2-8.12 PB3-6.93PC (n= 12, R2=0.81, P<0.05), but there was not highly relationship between the digestibility of ADF and carbohydrate contents (P>0.05). The elationship between digestibility of NDF and CNCPS contents was not significant (P>0.05).