Effect Of Alfalfa Silage Replaces Alfalfa Hay And Adding Rumen Buffers On Production Performance And Rumen Fermentation Of Dairy Cows

This study through the analysis of different water content of alfalfa silage nutritional value,the influence of alfalfa silage replace alfalfa hay,Mg O and tannin as rumen buffer to add the production performance of dairy cows and the influence of the rumen environment,explore Yanmen pass region alfalfa silage optimization using in the production of dairy cows.In Experiment 1,three moisture contents(45% moisture LM,60% moisture MM and70%moisture HM)of alfalfa were obtained by controlling the withering time,and ensiled.After 60 days of ensiling,the fermentation quality and nutritional value of alfalfa silage with different moisture content were analyzed.The results showed that MM group had the lowest silage p H,yeast count,NDF and ADF contents(P<0.05)and the highest(P<0.01)among three groups.MM group had higher lysine and methionine contents than those of HM group,but did not show a significant difference with LM group.The best quality of silage was to control the moisture content in 60% before alfalfa ensiled.In experiment 2,72 first birth cows were random Ly divided into two groups: H group cows fed TMR with alfalfa hay,and S group cows fed TMR with alfalfa silage,their performance,rumen fermentation characteristic,nutrient digestibility and blood metabolism indexes were determined.Compared with H group cows,the standard milk yield was slightly higher(P=0.06),and the milk fat content and digestibility of dry matter,organic matter,crude protein,crude fat and neutral detergent fiber were higher(P<0.05),but rumen p H was lower(P<0.05)after feeding for S group cows.The results indicate that the replacement of alfalfa hay by alfalfa silage could improve nutrient digestibility and milk fat content of dairy cows,but rumen p H was lower after feeding.In experiment 3,32 first birth cows were selected.Two factor design was used in the experiment.The first factor was alfalfa hay(H)or alfalfa silage(S),and the second factor was additive treatment(without additives C group or added with 100 g/d Mg O M group,100 g/d tannin T group and two combinations MT group).The performance,rumen fermentation characteristic,nutrient digestibility and blood metabolism indexes of dairy cows were determined.The results showed that TMR added with Mg O or tannin could increase the rumen p H after feeding(P=0.06)when cows fed alfalfa silage.Alfalfa silage TMR added with tannin,the cows had lower rumen NH3-N content(P<0.05),higher rumen MCP content(P<0.05),and slightly higher milk yield,standard milk yield and milk fat.The combination effect of the two additives is not good.Cows fed alfalfa hay TMR added with additives did not show significant results.In conclusion,tannin could improve the rapid reduction of rumen p H after morning feeding,which is conducive to the application of alfalfa silage in dairy cow.