Evaluate Of Associate Effects Between Alfalfa Hay And Millet Stalk

This study was proposed to investigate the associate effects of alfalfa hay and millet stalks,and explore the mechanism of associate effects by in vitro fermentation experiment,Nylon-bag technique and feeding experiment.We aimed to provide the basic data for rational utilization of millet stalks,and put forward reasonable advice for the selected evaluating indexes when studied associative effects by different ways.Experiment 1.Evaluating the associate effects of alfalfa hay and millet stalks by the method of in vitro gasThree non-pregnant Small-tailed Han sheep with installation rumen fistula were selected as rumen fluid donor.The roughage included alfalfa hay mixed with millet stalks according to the ration of 100:0,0:100,75:25,50:50,25:75 and then five mixed roughage was combined with concentrate by the proportion of 60:40 to constitute five complete diets(Ⅰ(A100M0),Ⅱ(A0M100),Ⅲ(A75M25),Ⅳ(A50M50),Ⅴ(A25M75)).We recorded the gas production(GP)at 2,4,8,12,24,36,48 h and measured the fermentation parameters(pH,microbiological crude protein(MCP),volatile fatty acid(VFA)and ammonia nitrogen(NH3-N)).The GP and MCP generation at 24 h were selected as the index to evaluate associate effects index(AEI).We used the variation of pH,VFA and NH3-N generation to reveal mechanism of the associate effect.The results showed as follow:(1)The GP,GP parameters,MCP,TVFA and NH3-N concentration were increased,and the concentration of TVFA and acetic acid were significantly improved(P<0.05)with the increasing of alfalfa hay proportion.However,the values of acetic/butyric were not affected(P>0.05),and the pH values varied from 6.71 to 6.98.(2)The AEI of Ⅲ,Ⅳ,Ⅴ group was 2.4%,7.5% and 6.9% separately,when the GP at 24 h was the only evaluating index.(3)The AEI of Ⅲ,Ⅳ,Ⅴ group was 4.6%,13.4% and 13.7% separately,when the MCP generation at 24 h was the only evaluating index.Experiment 2.Evaluating the associate effect of alfalfa hay and millet stalks with Nylon-bag techniqueFive non-pregnant Small-tailed Han sheep with installation rumen fistula were used as experimental animal We used Nylon-bag technique with 5×5 Latin Square design to measure the digestibility and effective degradability(ED)of major nutrition composition in diets(Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ)which were designed in Exp.1.We Used EDDM and EDCP as the first grade assessment index to calculate associate effects index(AEI),meanwhile,EDNDF and EDADF were used as the second grade assessment to reveal mechanism of the associate effect.The results showed as follow:(1)The ED of DM,CP,NDFand ADF were significantly increased with the increasing of alfalfa hay proportion(P<0.05).(2)The AEI of Ⅲ,Ⅳ,Ⅴ group was 0.8%,4.0% and 3.7% separately,when the EDDM was the only evaluating index.The AEI of Ⅲ,Ⅳ,Ⅴ group was 2.5%,3.5% and 3.1% separately,when the EDCP was the only evaluating index.So the diet of Ⅳ was the best.(3)In the diets of Ⅲ,Ⅳ,Ⅴ,the contribution rate of CF to associative effect of DM were 101.55%,68.75% and 55.41%.Experiment 3.Evaluating the associate effect of alfalfa hay and millet straw with feeding experiment—effects of different proportional alfalfa and millet straw on energy efficiency ratio and protein efficiency ratio of Small Tail Han SheepSixty one-year-old,non-pregnant Small-tailed Han sheep with similar body weight were randomly divided into four groups(each group with 3 replicates,each replicates with 5 ewes)fed with different diets(Ⅰ,Ⅱ,Ⅳ and Ⅴ),seperately,which were selected by Exp.1 and Exp.2.The feeding experiment lasted 40 days including 10 days for adjustment.After the feeding experiment,one ewe was selected randomly from each replicates to suffer the digestive experiment which lasted 7 days with 4 days for adjustment.We selected RGE(the ration of gain and energy)and RGP(the ration of gain and protein)as the index to estimate associate effects index(AEI)of different diets,and validated the conclusion of the experiment1 and experiment2.Test results show that:(1)With the increasing of alfalfa hay ration in diets,the feed intake and daily gain were increased,and the DMI of Ⅰ,Ⅳ and Ⅴwas significantly increased by 8.96%,6.39% and 7.91%,respecitively(P<0.05).Compared with group Ⅱ,the daily ADG of group Ⅰ and Ⅳ was increased significantly by 51.46% and 35.89%(P<0.05),and the ADG of group Ⅴ was increased by 21.36%,but the difference was not significant(P>0.05).(2)The AEI of Ⅳ,Ⅴ group was 7.5%,3.5% separately,when the RGE was the only evaluating index.(3)The AEI of Ⅳ,Ⅴ group was 4.5%,3.7% separately,when the RGP was the only evaluating index.The following conclusions could be reached according to the study above:(1)The AEI was different when evaluating the associate effect by fermentation experiment in vitro,Nylon-bag technique and feeding experiment.(2)The AEI was basically the same when evaluating the associate effect by the different ways.(3)The alfalfa hay with 25%~50% in roughage gained better positive associate effect,and alfalfa hay mixed with millet stalks according to the ration of 50:50 could obtain the best positive associative effect in terms of energy and protein conversion efficiency.(4)The feeding experiment was the most accurate method of evaluating associate effect.The accuracy of Nylon-bag technique was higher than that of In vitro because the conclusion gained by nylon bag technique was closer to that of feeding experiment.