Dann H M, Grant R J, Cotanch K W, Thomas E D, Ballard C S, Rice R
W. H. Miner Agricultural Research Institute, Chazy, NY 12921, USA.
J Dairy Sci. 2008 Feb;91(2):663-72. doi: 10.3168/jds.2007-0521.
Total mixed rations containing brown midrib sorghum-sudangrass silage (bmrSS) or corn silage (CS) at either 35 or 45% of dietary dry matter were fed to Holstein dairy cows to determine the effect on lactational performance and nutrient digestibility. Twelve cows were assigned to 1 of 4 diets in replicated 4 x 4 Latin squares with 21-d periods. In vitro 30-h neutral detergent fiber digestion, measured before the start of the trial, was 46.0% for CS and 58.3% for bmrSS. Dry matter intake was greatest when cows were fed the 35% CS (23.4 kg/d) and 45% CS (23.2 kg/d) diets, was least when cows were fed the 45% bmrSS diet (17.6 kg/d), and was intermediate when cows were fed the 35% bmrSS diet (20.1 kg/d). The bmrSS diets resulted in greater body weight gain per 21-d period but similar body condition scores compared with the CS diets. Yield of solids-corrected milk (SCM) was similar among the diets. Efficiency (SCM:dry matter intake) was 28% greater for cows fed the bmrSS than those fed the CS diets. In vivo digestibilities of organic matter and crude protein were greater for the CS diets than the bmrSS diets, but total tract digestibilities of neutral detergent fiber and starch were similar among diets. Ruminal pH was greater when cows were fed the 45% bmrSS diet (6.58), was least when cows were fed the 35% CS (6.10) and 45% CS diets (6.13), and was intermediate when cows were fed the 35% bmrSS diet (6.42). The ratio of acetate to propionate was greater for the bmrSS diets (2.77) than for the CS diets (2.41), with no difference among diets in total volatile fatty acid concentrations (122 mM). In conclusion, cows fed bmrSS had greater efficiency of SCM production, higher ruminal pH, and greater acetate to propionate ratios than cows fed CS. With these diets fed in a short-term study, bmrSS appeared to be an effective alternative to the CS hybrid when fed at either 35 or 45% of dietary dry matter.
将含有占日粮干物质35%或45%的棕色中脉高粱 - 苏丹草青贮饲料（bmrSS）或玉米青贮饲料（CS）的全混合日粮喂给荷斯坦奶牛，以确定其对泌乳性能和养分消化率的影响。12头奶牛被分配到4种日粮中的1种，采用重复的4×4拉丁方设计，每期21天。在试验开始前测定的体外30小时中性洗涤纤维消化率，CS为46.0%，bmrSS为58.3%。当奶牛饲喂35%CS（23.4千克/天）和45%CS（23.2千克/天）日粮时，干物质摄入量最大；当奶牛饲喂45%bmrSS日粮（17.6千克/天）时，干物质摄入量最小；当奶牛饲喂35%bmrSS日粮（20.1千克/天）时，干物质摄入量处于中间水平。与CS日粮相比，bmrSS日粮使每21天的体重增加更多，但体况评分相似。日粮间的固体校正乳（SCM）产量相似。饲喂bmrSS的奶牛的效率（SCM：干物质摄入量）比饲喂CS日粮的奶牛高28%。CS日粮的有机物质和粗蛋白的体内消化率高于bmrSS日粮，但日粮间中性洗涤纤维和淀粉的全肠道消化率相似。当奶牛饲喂45%bmrSS日粮时，瘤胃pH值最高（6.58）；当奶牛饲喂35%CS（6.10）和45%CS日粮（6.13）时，瘤胃pH值最低；当奶牛饲喂35%bmrSS日粮时，瘤胃pH值处于中间水平（6.42）。bmrSS日粮的乙酸与丙酸比值（2.77）高于CS日粮（2.41），日粮间总挥发性脂肪酸浓度无差异（122毫摩尔）。总之，与饲喂CS的奶牛相比，饲喂bmrSS的奶牛SCM生产效率更高，瘤胃pH值更高，乙酸与丙酸比值更大。在短期研究中饲喂这些日粮时，当bmrSS占日粮干物质的35%或45%时，它似乎是CS杂交品种的有效替代品。
