5种青贮饲料在奶牛瘤胃中的淀粉降解特性

Starch Degradation Characteristics of Five Kinds of Silage in the Rumen of Dairy Cows

本试验旨在研究苜蓿青贮、全株小麦青贮、燕麦青贮和全株玉米青贮(2种)共5种青贮饲料的淀粉瘤胃降解特性,对其有效降解率与实时降解率进行分析,以期能根据单个时间点的淀粉降解率来估算青贮饲料的淀粉降解率,并为《奶牛营养需要和饲养标准》的更新提供相关数据。选用4头装有永久性瘤胃瘘管的荷斯坦奶牛为试验动物,采用尼龙袋法评定淀粉的动态降解率和有效降解率,将装有待测饲料样品的尼龙袋在奶牛瘤胃中分别培养4、8、12、24、30、36、48和72h,每头牛每个时间点设4个平行。结果显示:(1)随着在瘤胃内培养时间的延长,各青贮饲料的淀粉瘤胃降解率均呈现逐步上升的趋势,且在24h后趋于稳定;全株小麦青贮的淀粉有效降解率最高,与依次降低的燕麦青贮、苜蓿青贮和全株玉米青贮差异显著(P<0.05)。(2)试验所选用的青贮饲料的8h淀粉降解率与其有效降解率相关性最强,R2为0.9876。由此可知,采用8h淀粉降解率估测青贮饲料在奶牛瘤胃中的淀粉降解率是可行的,本试验结果可为科学配制奶牛日粮提供数据参考。

This experiment was conducted to investigate starch degradation characters and analyze the effective degradation rate and real-time degradation rate in the rumen of 5 silages,including alfalfa silage,whole wheat silage,oat silage and 2 whole corn silages,in order to estimate starch degradation rate according to degradation rate of a single time and update the relevant data of starch in silages for Chinese Dairy Cattle Nutrient Requirements.4 Holstein cows with permanent ruminal cannulas were selected and nylon-bag technique was used to determine the dynamic and effective degradation rate of starch.The time points of nylon-bag technigue were 4,8,12,24,30,36,48 and 72 h in the rumen of dairy cows with 4 parallels for each cow.The results showed as follows:①The degradability of starch increased gradually over time,and tended to be steady after 24 h.The effective degradability of starch of whole wheat silage was significantly higher than that of oat silage,alfalfa silage and whole corn silage(P<0.05),which was decreased in turn.②There was a strong correlation between effective degradability and dynamic degradability of starch at 8 h with R 2 was 0.9876.It was viable that rumen degradability of starch at 8 h could be used to determine starch degradability of silage in the rumen of dairy cows.The results of the test had reference value for designing diet of dairy cows.