Rapid Evaluation Of Nutritional Value And Establishment Of Prediction Model For Whole-plant Corn Silage

This study aimed to establish a nutritional component database of whole-plant corn before and after silage based on the Cornell Net Carbohydrate and Protein System?CNCPS?,and to establish nutritional value prediction models by Near Infrared Spectrum?NIRS?.In addition,the ruminal degradation characteristics of whole-plant corn silage were determined by in vitro,and was calculated the correlation coefficients between nutrient components and effective ruminal degradation rate of whole-plant corn silage were calculated to find rapid assessment methods for the effective degradation rate of dry matter?DM?,starch and neutral detergent fiber?NDF?.We collected the whole-plant corn and their corresponding silage samples from 17 dairy farms,evaluated the nutritional value of these samples using the CNCPS,and detected the ruminal degradation characteristics of the whole-plant corn silage by in vitro.The main results are as follows:1.Conventional components and CNCPS components analysis and prediction models establishment for raw whole-plant corn materialsThe DM,organic matter?OM?,crude protein?CP?,ether extract?EE?,neutral detergent fiber?NDF?,acid detergent fiber?ADF?,acid detergent lignin?ADL?,Starch,neutral detergent insoluble Protein?NDIP?,acid detergent insoluble protein?ADIP?and soluble protein?SP?,carbohydrate?CHO?,non fiber carbohydrates?NFC?,starch?CB1?,soluble fiber?CB2?,digestible fiber?CB3?,indigestible fiber?CC?,insoluble true protein?PB1?,fiber conjugated protein?PB2?and undegradable protein?PC?prediction models of raw whole-plant corn materials were established by NIRS.The models could be used to quickly predict its nutrient contents.NFC showed strong correlation with NDF,CP,and OM?R²=0.924?.PC showed low correlation with DM,NDF,ADF,OM,starch,EE and CP?R²=0.316?.PB1 showed low correlation with CP,NDIP,and ADIP?R²=0.518?.2.Conventional components and,CNCPS components analysis and prediction models establishment for whole-plant corn silageThe DM,OM,CP,EE,NDIP,CHO,NFC,CA1 and starch prediction model of whole-plant corn silage were established by NIRS.The models could be used to quickly predict its nutrient contents.CHO showed strong correlation with EE and OM?R²=0.929?.NFC showed strong correlation with NDF,CP,and Ash?R²=0.986?.CC showed strong correlation with NDF?R²=0.998?.PB1 showed strong correlation with CP,DM,SP,NDF,and ADF?R²=0.666?.PB2showed strong correlation with NDIP?R²=0.713?.3.Study on ruminal degradation characteristics of starch,DM,and NDF in whole-plant corn silage and the establishment of prediction modelsThe ruminal degradation parameters and effective degradation rate of the whole-plant corn silage with different storage time were different.The ruminal degradation rate of DM,starch,and,NDF were highest when stored for 60 d,which were 33.40%,78.91%and 25.53%,respectively.The effective degradation rate of DM were positively correlated with CP content,and negatively correlated with NDF and ADF contents.The effective degradation rate of starch was positively correlated with starch content.The effective degradation rate of NDF were negatively correlated with NDF and ADF contents,and positively correlated with CP and OM contents.The effective degradation rate of DM were positively correlated with NFC content,and negatively correlated with CHO,CB3,and CC contents.The effective degradation rate of starch were positively correlated with CHO and NFC contents,and negatively correlated with CA1,CA2,CA4,and CB2 contents.The effective degradation rate of NDF were negatively correlated with CHO,CB3,and CC content,and positively correlated with NFC contents.Prediction equations for effective degradability of DM and starch using CP,NDF,ADF,and starch as prediction factors were ED_?DM?=54.777-0.439 NDF-0.004 ADF?R²=0.973,n=51,P<0.0001?;ED_?Starch?=55.434+0.987 starch?R²=0.843,n=51,P<0.0001?;and ED_?NDF?=75.786-0765CP-1.036NDF+0.310ADF?R²=0.879,n=51,P<0.0001?,respectively.Prediction equations for effective degradability of DM and starch using CHO,NFC,CB3,CHO,NFC,CA2,CA4,CB2,and CC as prediction factors were ED_?DM?=66.158-0.488 CHO+0.330NFC-0.079 CC?R²=0.980,n=51,P<0.0001?;ED_?Starch?=45.754-3.564 CA4-0.827 CB2+0.159 CHO-0.692CA2+0.960NFC?R²=0.894,n=51,P<0.0001?;and ED_?NDF?=41.972-0.457CHO+0.753NFC-0.697CC?R²=0.810,n=51,P<0.0001?,respectively.In summary,the study provided chemical analysis data of raw whole-plant corn materials and their silage under the experimental conditions,and established rapid prediction models for main nutrients by NIRS.In addition,the mathematical models of the effective degradation rate nutrients,DM,starch,and NDF in whole plant corn silage were established,which were beneficial to rapidly evaluate the nutritional value of whole plant corn in farms.