Fermentation Characters And Nutritional Value Of Alfalfa Silages Ensiled With Formic Acid Or Italian Ryegrass

Alfalfa(Medicago sativa)was ensiled with formic acid or Italian ryegrass(Lolium multifolorum)in this study.Dynamic of silage fermentation characters and protein degradation were recorded.Nutritional values of the silages by the 30th day of fermentation were also evaluated.Alfalfa silages with five levels FA(0,1,2,3,4 mL/kg fw)were evaluated at 8 specified time period(0.5,1,2,3,5,7,15,and 30 days).Results showed that formic acid treated silages had a better fermentation quality evidenced by lower pH,higher water soluble carbohydrate concentration(WSC)and dry matter content(DM),as well as promoted homolactic fermentation and inhibited butyric fermentation.Total N(TN)content varied little with FA level or time ensiling,a rapid increase of NPN concentration occurred post-ensiling.Silage treated with higher formic acid levels had a slightly higher level of total NPN,but significantly lower level of NH3-N than the control.Highest levels of peptide-N found with the highest FA level,and more peptide-nitrogen(Peptide-N)were protected from degraded into free amino acid(FAA-N)when formic acid was applied 3 to 4 mL/kg.Thus,applying formic acid to alfalfa by 4 mL/kg is the best.In the 30 day post-ensiling,nutritive values of silage treated with formic acid or not were compared.Results showed that dry matter increases with the increase of formic acid application,FA4 got the most.Neutral detergent fiber increased after little decrease,FA2,FA3 significantly lower than the control FA0.However,formic acid leads to crude protein lossing,and lower applications(FA1,FA2)of formic acid showed not conducive to the preservation of alfalfa quality protein components PB2.PA + PA of alfalfa treated with lower formic acid were significantly higher than control,while PB2 + PB3 which can flow to the post digestive tract of animal were less than the control.The silage ensiled with alfalfa alone showed the best protein structure,alfala silage with 4mL/kg formic acid was better,but alfalfa with 4mL/kg formic acid preaerved more dry matter and ether extract.Alfalfa and ryegrass silage mixed with different mass ratio[10:0(A10B0),8:2(A8B2),6:4(A6B4),4:6(A4B6),2:8(A2B8),0:10(A0B10)]were evaluated at 5 specified time period(1,3,7,15 and 30 days).Results showed that all treatments fermented very well,all produced low acetic,propionic and butyric acid.Alfalfa and Italian ryegrass ensiled together is better than ensiled alone.Most of nonprotein nitrogen of alfalfa silage was peptide nitrogen,while Italian ryegrass silage was smaller molecule nitrogen like free amino acid.A6B4 achieved lower pH,save more dry matter,more total nitrogen with fewer non-protein nitrogen,therefore alfalfa and ryegress mixed by 6:4 was the best.In the 30 days post-ensiling,nutritive value of each ratio were campared.Results showed that large quantities of non-protein nitrogen were produced during ensiling.Crude protein increases with the increase proportion of alfalfa,as well as neutral detergent NDIP.A6B4 got the most eather extract,the least binding proteins(PC),though less total protein than higher alfalfa proportions.A6B4 also got the least PA + PB1 and the highest PB2 + PB3.Therefore,A6B4 and protein nutritional quality is better.