两种纤维来源日粮对奶牛胃肠道甲烷排放的影响

发布时间：2018-11-21 12:34

【摘要】：本论文研究稻草秸秆(RS组)和青贮玉米+稻草秸秆(MF组)纤维日粮对奶牛瘤胃发酵、泌乳性能和胃肠道甲烷排放的影响。论文分成两部份：1)通过体外模拟瘤胃发酵,探究瘤胃微生物对两种纤维日粮底物的降解特性、发酵特征和甲烷生成的影响：2)通过奶牛饲养试验,研究两种纤维日粮对奶牛瘤胃发酵、养分摄入、消化和利用、泌乳性能和胃肠道甲烷排放的影响：通过48h体外模拟瘤胃发酵试验,测定发酵产气量、干物质消失率、挥发性脂肪和甲烷产量等。与RS组相比,MF组的pH显著降低,干物质消失率、总挥发性脂肪酸总量、48h产气量和起始底物降解速率显著升高。这显示,MF组日粮底物中的青贮玉米纤维更容易被瘤胃微生物降解。另外,与RS组相比,MF组的丙酸产量显著升高,乙丙比值和甲烷含量显著降低。表明MF组中的青贮玉米纤维更倾向于丙酸型发酵,进而减少了甲烷生成。挑选14头体况相近的泌乳中后期荷斯坦奶牛作为试验动物,根据产奶量、胎次和泌乳日龄将奶牛配对分成2组。预饲期15天、正饲期28天(消化试验、采集瘤胃液、测定奶牛泌乳性能和胃肠道甲烷排放量等)。与RS组相比,MF组的DMI、 GEI和NDFI显著升高,且NDF消化率亦显著升高。证明青贮玉米具有更好的适口性,且青贮玉米纤维更容易被奶牛消化利用。MF组乳中固形物、乳蛋白、乳脂肪的产量和含量均显著高于RS组,与稻草秸秆纤维相比,日粮青贮玉米纤维明显提高了奶牛的泌乳性能。MF组的甲烷能转化因子和单位奶产量的甲烷排放量显著低于RS组。结果显示,与稻草秸秆纤维相比,日粮青贮玉米纤维有助于减少奶牛胃肠道甲烷相对排放。综合上述：与单一稻草秸秆作为日粮纤维来源相比,以青贮玉米作为日粮的主要纤维来源提高了奶牛采食量、纤维消化和利用以及奶牛泌乳性能,并减少了甲烷转化因子和单位产奶量的胃肠道甲烷排放。
[Abstract]:The effects of fiber diet of straw (RS group) and silage corn straw (MF group) on rumen fermentation, lactation performance and methane emission from gastrointestinal tract were studied. This paper was divided into two parts: 1) the degradation characteristics, fermentation characteristics and methane production of rumen microbes on the substrate of two fiber diets were studied by simulating rumen fermentation in vitro; The effects of two fiber diets on rumen fermentation, nutrient intake, digestion and utilization, lactation performance and gastrointestinal methane emission were studied. Volatile fat and methane production. Compared with RS group, pH of MF group decreased significantly, dry matter disappeared rate, total volatile fatty acid content, gas production at 48 h and degradation rate of initial substrate increased significantly. The results showed that silage corn fiber in dietary substrate of MF group was more easily degraded by rumen microorganism. In addition, the yield of propionic acid in MF group was significantly higher than that in RS group, while the ratio of ethylene-c and methane content was significantly decreased in MF group. The results showed that silage corn fiber in MF group was more inclined to propionic acid fermentation, thus reducing methane production. 14 Holstein cows with similar body condition were selected as experimental animals. The cows were divided into two groups according to milk yield, birth order and lactation age. The pre-feeding period was 15 days and the positive feeding period was 28 days (digestibility test, rumen fluid collection, lactation performance and methane emission from gastrointestinal tract, etc.). Compared with RS group, DMI, GEI and NDFI in MF group were significantly increased, and NDF digestibility was also significantly increased in MF group. The results showed that silage maize had better palatability, and silage corn fiber was easier to be digested and utilized by dairy cattle. The yield and content of solids, milk protein and milk fat in MF group were significantly higher than those in RS group, compared with straw fiber. Dietary silage corn fiber significantly improved the lactating performance of dairy cows, and the methane conversion factor and methane emission per unit milk yield in MF group were significantly lower than those in RS group. The results showed that compared with straw fiber, dietary silage corn fiber could reduce relative methane emission from gastrointestinal tract of dairy cows. Compared with single straw as dietary fiber source, silage corn as the main fiber source improved the feed intake, fiber digestibility and utilization and lactation performance of dairy cows. Methane conversion factors and gastrointestinal methane emissions per unit milk yield were also reduced.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S823.5

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