[目的]本研究旨在探讨奶牛TMR中,粗饲料羊草长度对奶牛采食行为、瘤胃发酵和日粮消化率的影响.［方法］试验动物为3头体重496士23 rnkg,安装有永久性瘤胃瘘管的健康中国荷斯坦奶牛.采用3×3拉丁方设计.用36% NDF不同羊草长度（9 cm、5 cm和1 cm）的三种全混合日粮饲喂奶牛.［结果］:①奶牛DMI和NDFI不受羊草长度影响;采食、反刍和总咀嚼时间随着羊草长度的减小显著减少.②羊草长度为1 cm时瘤胃pH显著低于9 cm和5 cm组;瘤胃内NH3-N浓度在5 cm组最高,与1 cm组差异明显;随着羊草长度减小,乙酸浓度和乙酸与丙酸的比例显著降低,丙酸浓度升高,总VFA和丁酸浓度不受羊草长度影响.③日粮中DM、CP、NDF和ADF消化率在羊草长度为5 cm时显著高于其他两组.表明饲草长度的减小会缩短采食、反刍和咀嚼时间,但过短会使瘤胃pH显著降低;适当长度可提高日粮营养成分的消化率.［结论］综合评价本试验结果以羊草长度为5 rncm更适合全混合日粮配制.%To study effects of particle sizes of forage in TMR on feed intake, chewing activity, ruminal fermentation and diet digestibility of rumen fistulae were arranged as 3× 3 Latin Square design for three TMR diet. Forage sizes of three TMR were 9 cm, 5 cm and 1cm, respectively. Dry matter intake and neutral detergent fiber intake were not affected by the sizes of Chinese wildrye. Feed intake, ruminating and chewing time decreased significantly with decreasing sizes of Chinese wildrye. Rumen pH value was significantly lower in length 1cm of Chinese wildrye diet than 9 cm and 5 cm. Rumen ammonia nitrogen concentration was significantly higher in cows fed 5 cm of Chinese wildrye diet than fed 1cm of Chinese wildrye diet. When the forge size decreased, acetate and ratio of acetate to propionate in rumen decreased significantly and propionate increased, while total volatile fatty acid and butyrate were no effected .Digestibility of DM, CP, NDF and ADF were significantly higher in cows fed length 5 cm Chinese wildrye diet than the other diets. These results indicated that intaking time, ruminating time and chewing time decreased with decreasing of length of Chinese wildrye. When the Chinese wildrye was too short, rumen pH value could be induced very low. Digestibility of diets possibly increased with feasible length of Chinese wildrye. It implicates that the length 5 cm of Chinese wildrye was feasible in TMR.
展开▼
