| In agricultural literature,it has been increasingly important to increase the supply of maize products through restructuring the supply chain,increasing the number of research stations,expanding maize farming size,and improving the efficiency of maize stover’s conversion.This research focuses on maize stover and aims to investigate both the theories and the methods used to improve the efficiency of maize stover conversion.By combining the theories employed in the fields of Agrostology and Animal Nutrition and using the methods of in virto fermentation,the study specifically examines how the ensiling quality of maize stover and its silage varies with maize cultivars and post-harvest exposure days.The study would not only help increase silage supply through the improvement of conversion efficiency,but also assist in relieving the consumption competition between human and livestock over maize.The research chooses three different maize cultivars(i.e.,Jintian,Jinnuo,and Xianyu)planted in Tumote region as research objects and sets seven different storage periods(i.e.,0 day,7 days,15 days,30 days,60 days,90 days and 180 days).In particular,the relationships between the quality of maize stover and its silage and maize cultivars as well asexposure days are examined by analyzing four indexes: 1)the nutrition content of maize stover and its silage;2)the quantity of microbial;3)the quality of fermentation;and 4)the changing of in vitro fermentation characteristics.The results are shown as follows:(1)Based on the nutrition contents of maize stover and its silage,DM content varied with maize cultivars,and Jintian maize stover and its silage possessed higher DM content.Speaking of the relationship between quality and exposure days,the quality of maize stover and its silage decreased with time.After 7days,15 days,30days of placement,the contents of OM in Maize stover changed into +2.77%、+2.26%、+2.77% respectively.The amplitude of variation of CP was-15.22%、-12.62%、-15.22%.And NDF changed into-8.49%、-11.49%、-8.46%,and the variation range of ADF was +8.91%、+13.29%、+8.67% separately.After 30 days of placement,for the silage of maize stover,the rangablity of OM,CP,NDP,and ADP were 1.32%,-9.04%,-4.51%,and-9.58%,respectively.(2)Given the quantity of microbial,the quantity of microbial was also different among different maize cultivars.Particularly,the number of lactic acid bacteria was found to be higher for Jintian and Jinnuo Maize stover and their silage.During of the effect of exposure days,the number of lactic acid bacteria decreased with time,while the numbers of saccharomycetes,mildew,and aerobic bacteria tended to increase over time.After 7days,15 days and 30 days of placement,the number of lactic acid bacteria in maize stover and its silage decreased inro-4.23%、-1.01%、-3.22% and +8.60%、+1.58%、-7.16% respectively.(3)Provided by the quality of fermentation,it was highest for Jintian maize stover and its silage.As time to increase,the pH value,and the contents of acetic acid,propanoic acid,butyric acid,and ammonia nitrogen trended upward,while the content of lactic acid bacteria trended downward.After 7days,15 days,30 days of placement,the PH value increased by 2.83%、9.77%、12.85%;the contents of acetic acid increased by7.14%、16.07%、33.93%;the propionic acid increased by 0.00%、183.33%、150.00%;and ammonia nitrogen increased by 136.36%、118.18%、429.09%,respectively.On the other hand,the content of lactic acid bacteria decreased by 10.50%、51.93%、41.99% as well.(4)For the transforming of vitro fermentation characteristics,Jintian maize stover and silage had higher in vitro fermentation quality than the other two maize cultivars.In terms of the relationship between the quality of maize stover and its silage and exposure days,the pH value of rumen fluid in maize stover and its silage appeared to increase as time.On the contrary,the values of TFVA,IVDOM and GP tended to decrease.After 7days,15 days,30days of placement,the pH value of rumen fluid in maize stover went up to 0.65%、0.81%、1.30%;the values of TFVA fell by-0.80%、-3.49%、-5.56%;GP decreased by 0.43%、1.40%、5.40%,and IVDOM in maize stover decreased by1.65%、5.09%、8.19% respectively.After 30 days of placement,while pH、TVFA、GP and IVDOM in the silage rose by +2.44%、-4.89%、-4.50%,and-4.01%.(5)The results mentioned above clearly revealed the nutrition content of maize stover and its silage,the quantity of microbial,the quality of fermentation,and the changing of in vitro fermentation characteristics,which varied highly with maize cultivars and post-harvest exposure days.After the fermentation of maize stover,the contents of DM,NDF,ADF,WSC decreased,however,the contents of EE,CP,OM seemed to be unchangable.According to the quantity of microbials,the number of lactic acid bacteria were increasing,on the contrary,the numbers of saccharomycetes and aerobic bacteria were decreasing.In addition,the pH,GP,TVFA,and IVDOM value of rumen fluid decreased significantly.To conclude,the quality of maize stover is found to decrease as time progressed.To acquire high quality silage,it would be optimal to make the silage right after harvest.If this is not possible,people are suggested making the silage within 30 days to ensure the fermentation. |
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