| This study was carried out to evaluate the fermentation with mixture of whole-crop corn and common vetch at different rates, and determine the best mixed rate. The additives were also used to improve the fermentation quality of bi-crop silage in this study. The additives are CE (0.003% FW),LF (0.001% FW) and CE+LF (0.001%+0.003% FW) The silos were opened on 1,3,5,15, and 45 days of ensiling, separately. Three silos are used for each treatments and ensilage days.Experiment I:Effect of different mixed ratios on fermentation quality of bi-crop silage.Whole-crop corn and common vetch were chopped, and mixed in ratios of 1:1,1:2,2:1 (fresh weight basis) and ensiled in laboratory vacuum bags. The pH value of 2:1 ratio decreased quickly during the early stage of ensiling. The values of pH and AN/TN were lower (p<0.05), whereas the contents of LA and WSC were higher (p<0.05) than other bi-crop ratios. It showed that the 2:1 ratio increased the content of WSC and the fermentation was dominated by lactic acid bacteria. The pH value of bi-crop silage did not reach below of 4.2 after 45 days of ensiling. Meanwhile, all treatments had low content of LA and high content of BA and AN/TN. According to general evaluation of fermentation quality of silage, it was suggested that the fermentation quality of 2:1 ration was the best. It had lowest pH value (4.88), and higher contents of LA, WSC and lower content of AN/TN. It was suggested that the bi-crop silage of three rations were not better.Experiment II:Effect of adding CE on fermentation quality of bi-crop silage.The bi-crop ratios were the same as ExperimentⅠ. The results showed that the pH value and the AN/TN of adding CE were lower than control, however LA increased significantly (p<0.05) during early stage of ensiling, and CE treatment could increase more fermentation substrate and effectively inhibited the proteolysis by aerobic microorganisms in the early stage of ensiling. The bi-crop silage with CE treatment improved the fermentation quality as compared with control after 45 days of ensiling. All treatments decreased significantly(p<0.05)the pH value and content of BA, and increased the contents of LA and WSC, the pH of the 2:1 bi-crop ration had a largest drop (4.2) and AN/TN was lower significantly (p<0.05) than control, because of the lower WSC content and higher buffering capacity of 1:2 ration, the fermentation quality was not better and the pH value was over 5.0, it indicated that 1:2 bi-crop ration with CE treatment could not improve the fermentation quality.ExperimentⅢ:Effect of adding LF on fermentation quality of mixed silage.The ration of bi-crop silage was the same as ExperimentⅠ.The pH value of all treatments with adding LF had a quick drop, as well as a quick increase of LA during early stage. The values of pH and AN/TN, and BA (p<0.05) were lower than control. It showed that the fermentation was dominated by lactic acid bacteria and the activity of other undesired microorganisms was inhibited. It decreased the loss of protein and improved the fermentation quality. The quality of 1:1 and 2:1 rations with adding LF was the best with low pH (4.2) and BA content, and the high contents of LA and WSC. It was suggested that the fermentation quality and the feeding value of silage of 1:1 and 2:1 rations with adding LF was improved, however LF had not effectively improve the fermentation quality of 1:2 bi-crop ration.Experiment IV:Effect of adding CE+LF on fermentation quality of bi-crop silage.The bi-crop ration of silage was the same as ExperimentⅠ.The result showed that the pH value with additives had a quick drop and the LA had a quick increase during the early stage of ensiling. The values of pH and AN/TN with additives treatment decreased significantly (p<0.05) and the LA increased significantly (p<0.05) as compared with control in the early stage of ensiling. After 45 days of ensiling, the pH and AN/TN values, and BA of silage with adding CE+LF were significantly lower and the LA content was higher than control (p<0.05). The fermentation quality of all treatments was better than the control, and the fermentation quality of 1:1 and 2:1 rations with additives was the best. They had the pH values of 4.28 and 4.20, respectively, and higher WSC content and lower AN/TN value. |
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