Nutritional Value Of FRsilage And Effects On Production Performance Of Holstein Bulls

In this paper Cornell Net Carbohydrate and Protein System(CNCPS)and nylon bag technique were used to evaluate the nutritional value of mixed silage(french fries by-product and rice straw,FRsilage)and whole corn silage(WCsilage),and the best combination ratio was screened out by in vitro and in vivo experiments,to provides a scientific theoretical basis for the utilization of FRsilage of Holstein bulls production.Experiment 1:Comparison of fermentation characteristics and CNCPS components of FRsilage and WCsilageThis experiment was to evaluate and compare the nutrient value and rumen degradation rate of FRsilage and WCsilage by sensory evaluation,fermentation index,chemical nutrient analysis,nylon bag technique and according to CNCPS to provide a reference for the use of FRsilage in beef cattle breeding.The rice straw and frence fries by-product(1:2 DM basis)was mixed with silage additive,sealed for 60 days to get FRsilage(DM content at 35%).The results showed that:1)The sensory scores of the both feeds were Grade1.2)The pH of FRsilage was greater(P<0.01),whereas the concentration of lactic acid was lower than that of WCsilage(P<0.01).3)Though the DM content were similar between FRsilage and WCsilage(P>0.05),the content of CP,NDF,ADF in FRsilage were greater(P<0.01),while the content of starch and EE was lower in WCsilage(P<0.01).4)Compared with WCsilage,PB1,CA,CB2 and CC were greater(P<0.05),however PC,CHO,NSC and CB1 were lower in FRsilage(P<0.01).5)The 48h rumen digestibility of DM,CP and starch in FRsilage was 14.68%,7.79%and 4.09%lower than WCsilage,whereas the rumen digestibility of NDF and ADF were not affected by treatment(P>0.05).In conclusion,compared with the WCsilage,the CP content of FRsilage were higher,and the starch content was lower,which could be used as high-quality roughage resources for ruminants.Experiment 2:Evaluation of combination effects between FRsilage and WCsilage by gas production technique in vitroThe aim of this study was to evaluate the combination effects between FRsilage and WCsilage.Treatments were divided into seven combinations of the FRsilage and WCsilage in different ratios:0:100(T0),20:80(T20),40:60(T40),50:50(T50),60:40(T60),80:20(T80)and 100:0(T100)on DM and each combination had three replicates.In vitro gas production method was performed to measure DMD,pH,NH3-N,MCP,VFA at 48 h of incubation,the gas production(GP)was recorded at 2,4,6,8,10,12,24,36,and 48 h of incubation,the single factor associative effects index(SFAEI)and multiply factors associative effects index(MFAEI)of different combinations were calculated.The results showed that:1)GP and DMD decreased linearly with the increase of FRsilage(P<0.05),The SFAEI of GP and DMD were the lowest in T50 and T80 groups,whereas the highest in T20 group.2)The pH value of different combinations varied from 6.46 to 6.59,and SFAEI was the highest in T80 group.3)There was no difference in NH3-N concentration and MCP production among different combinations(P>0.05),but the highest was in T40 group,while the SFEAI of NH3-N and MCP were highest in T40 and T80 groups.4)The concentration of acetic acid,propionic acid,valeric acid and TVFA in T0 group was the highest,while that in T100 group was the lowest,and the difference between the two groups was extremely significant(P<0.01).Butyric acid was also the highest in T0 group,but the lowest in T80 group.Moreover,the greatest SFAEI of acetic acid,propionic acid and butyric acid were observed in T80,T20 and T60 groups respectively.According to MFAEI index evaluation,T40 group(40:60)was the best.Experiment 3:Effects of different proportions of FRsilage in diets on production performance and blood biochemical indexes of Holstein bullsThe purpose of this experiment was to explore the effects of different proportions of FRsilage instead of WCsilage on production performance,blood biochemical indexes and economic benefits of Holstein bulls.Sixty Holstein dairy bulls with similar body weight(461.33±33.47 kg)were randomly divided into four groups with 15 cows in each group.The four treatment groups were T20(concentrate+20%FRsilage+80%WCsilage),T40(concentrate+40%FRsilage+60%WCsilage),T60(concentrate+60%FRsilage+40%WCsilage)and T80(concentrate+80%FRsilage+20%WCsilage),the ratio of concentrate to roughage and the composition of concentrate were the same in the experimental group.Experimental periods lasted for 150 d.The results showed that:1)the ADG of Holstein bulls was not affected by different proportions of FRsilage instead of WCsilage(P>0.05).The F/G of T40 group was lower than that of the other three groups(P<0.05).2)The apparent digestibility of DM,NDF,ADF and EE decreased linearly with the increase of FRsilage(P<0.05).3)The concentrations of NH3-N and TVFA decreased linearly with the increase of FRsilage(P<0.01),whereas acetic acid content increased linearly with the increase of FRsilage(P<0.05).4)Serum ALB,Glu and TG decreased linearly with the increase of FRsilage(P<0.05).Glu in T40 group was greater than that in T80 groups(P<0.01),and UN in T80 group was lower than that of the former two groups(P<0.01).5)The economic benefit of T40 group was the highest.In conclusion,when 40%WCsilage was replaced by FRsilage,the production performance was the best and the economic benefit was the highest.