Study On Oat Silage Quality At Different Harvest Periods In Xinjiang Province

In order to screen high-quality silage oat varieties suitable for cultivation in Shihezi area and their optimal harvesting period,In this experiment,10 varieties of oats were selected in four growth stages（Heading stage、Milky stage、Wax ripening stage、Ripening stage）The forage quality was evaluated by membership function and the suitable growth period of silage was screened.Ten oat varieties were cut at two stages（heading stage and milk stage）.The collected samples were silage separately.The changes of nutritional quality and fermentation quality of oat silage at 0,3,5,9,15,30,45,60 D were studied,and the degradation process of nutrients in rumen of oat silage and silage for 60 d in rumen for 0-72 h was studied.The main results are as follows:1.Study on nutritional quality of oats in different harvest periodsOat hay,as the main preparation method of oats,has different nutritional quality due to harvest time.It was found that there were significant differences in nutritional quality of oat in heading stage,milk stage,waxy stage and maturity stage（P<0.05）.According to the results of nutrition quality and the analysis of membership function,the results showed that:1)The fresh grass yield and CP content of oat were the highest at heading stage,hay yield and WSC content at milk maturity stage and RFV value at maturity stage;2)The highest hay yield was 8.59 t/hm²,11.51 t/hm²and 10.50 t/hm²at heading stage,waxy stage and mature stage,and 14.62 t/hm²at milk stage.CP content at heading stage was higher than that at milk stage,waxy stage and mature stage.The CP content of Avena sativa‘Ever’was the highest at heading stage,milk stage and maturity stage,which were 15.74%,13.57%and 11.56%,respectively;3)According to the membership function evaluation,the comprehensive evaluation of Avena sativa‘Meida’at heading stage was the highest,that of milk ripening stage was the highest,and that of Avena sativa‘Ever’was the highest at waxy and mature stages;4)The peak yield of fresh grass of all varieties appeared at heading stage and milk ripening stage.It was suggested to select heading stage and milk maturity stage for silage processing.2.The effect of different harvest time on the quality of oat silageThe fermentation stage,growth period and silage fermentation time had significant effects on the quality of oat silage（P<0.05）.During the fermentation process,the nutrient content decreased gradually with the fermentation time,and the crude fiber content increased significantly with the increase of growth period,while the CP and WSC contents decreased.For the fermentation indexes in the fermentation process,the p H value decreased gradually,the organic acid content increased,and the NH₃-N/TN value increased gradually.The lactic acid content was the highest,acetic acid content was the lowest,and NH₃-N/TN was the lowest at heading stage.The fermentation quality of oat silage at milk ripening stage was better than that at heading stage.In this study,the quality of oat silage in milk ripening stage was better than that in heading stage.Compared with other oat varieties,Avena sativa‘Leader’had the best silage quality no matter at heading stage or milk ripening stage.It is suggested that Avena sativa‘Leader’oat silage should be planted in the local area,and the main mode of local oat silage production is to harvest this variety at milk ripening stage.3.Analysis and evaluation of rumen degradation rate of different oat hay and silageIn order to further screen out oat varieties and harvest time suitable for local promotion,this study analyzed and evaluated the semi-in-vitro digestibility of hay and silage of 10 oat varieties in two harvest periods,and calculated the parameters of effective digestibility model by least square method,and evaluated by membership function:The higher the DMD,the higher the feed intake of oat forage was,and the effective degradation rate of ADF and NDF was negatively correlated with the feed intake of livestock.It was suggested that mowing and silage at heading stage could obtain higher DMD forage,among which,oat king,Avena sativa‘Ever’and Avena sativa‘Leader’could obtain higher rumen degradation rate by cutting and silage at heading stage and milk ripening stage.Combined with the conclusion of Experiment 2,it is suggested that the main mode of local oat silage production is harvest at milk maturity stage of Avena sativa‘Leader’and Avena sativa‘Ever’.