Richards C J, Pugh R B, Waller J C
Department of Animal Sciences, The University of Tennessee, Knoxville, 37996, USA.
J Anim Sci. 2006 Mar;84(3):678-85. doi: 10.2527/2006.843678x.
Six steers (288.6 +/- 2.1 kg of BW) fitted with rumen and duodenal cannulas were used in a crossover design to evaluate intake, rumen fermentation, and site of nutrient digestion of freshly clipped, endophyte-infected (E+) Kentucky 31 tall fescue with or without soybean hull (SH) supplementation at 0.60% of BW (OM basis). Steers were placed in metabolism units within an environmentally controlled room and provided with free-choice access to fresh forage, water, and a vitamin/mineral supplement. The spring growth of E+ tall fescue was harvested daily during the experiment. Supplement was fed at 0700 with approximately 65% of the estimated daily forage. To maintain a fresh forage supply, additional forage was stored in a cooler and fed at 1900. Periods were 21 d with 14 d of adaptation and 7 d of digesta sample collection. Chromic oxide was used as a marker of duodenal digesta flow. Duodenal samples were taken 4 times daily with times shifting by 1 h each day to represent all 24 h of a day. Treatments were considered significant at P < 0.05. Supplementation of SH decreased forage OM intake from 1.64 to 1.41% of BW but increased total OM intake from 1.64 to 2.01% of BW. Apparent percentages (53.1%) and quantities (2,786 g/d) of rumen OM disappearance were not affected by supplementation. Percentages of total tract OM disappearance were not different (70.8%). Percentages of apparent rumen NDF disappearance also were not different (65.6%). Percentages of N disappearance were not different. Supplementation of SH resulted in increased total N (34.1 g/d) and microbial N (17.1 g/d) flowing to the duodenum. Rumen pH (6.5) was not affected, and rumen ammonia concentrations exhibited a time x treatment interaction in which SH decreased ammonia for 12 h after supplementation. Total VFA concentrations (103.9 mM) were unaffected. Liquid dilution rate (12.7%/h) and rumen OM fill (4.3 kg) were not different between treatments. Supplementation of SH at a rate of 0.60% of BW (OM basis) to calves consuming fresh E+ tall fescue decreased forage consumption but resulted in greater total intake, greater flow of N to the duodenum, and increased total tract OM disappearance.
选用6头安装了瘤胃和十二指肠瘘管的阉牛（体重288.6±2.1千克），采用交叉设计，以评估新鲜刈割的内生真菌感染（E+）肯塔基31高羊茅在添加或不添加占体重0.60%（以有机物计）的大豆皮（SH）时的采食量、瘤胃发酵及养分消化部位。阉牛被安置在环境可控的代谢笼中，可自由采食新鲜牧草、饮水及维生素/矿物质补充剂。实验期间，每天收割E+高羊茅的春季生长部分。补充剂于早上7点投喂，约占估计每日牧草量的65%。为保持新鲜牧草供应，额外的牧草储存在冷藏箱中，并于晚上7点投喂。每期时长为21天，其中14天用于适应，7天用于采集消化物样本。氧化铬用作十二指肠消化物流失的标记物。每天在十二指肠采集4次样本，每次采集时间提前1小时以使样本代表一天中的24小时。当P<0.05时，处理被认为具有显著性差异。添加SH使牧草有机物采食量从占体重的1.64%降至1.41%，但使总有机物采食量从占体重的1.64%增至2.01%。瘤胃有机物消失的表观百分比（53.1%）和数量（2786克/天）不受添加物影响。全消化道有机物消失百分比无差异（70.8%）。瘤胃中性洗涤纤维消失的表观百分比也无差异（65.6%）。氮消失百分比无差异。添加SH使进入十二指肠的总氮（34.1克/天）和微生物氮（17.1克/天）增加。瘤胃pH值（6.5）不受影响，瘤胃氨浓度呈现时间×处理交互作用，即添加SH后12小时内氨含量降低。总挥发性脂肪酸浓度（103.9毫摩尔）未受影响。不同处理间的液体稀释率（12.7%/小时）和瘤胃有机物充盈量（4.3千克）无差异。以占体重0.60%（以有机物计）的比例向采食新鲜E+高羊茅的犊牛添加SH，降低了牧草采食量，但使总采食量增加、进入十二指肠的氮流量增加且全消化道有机物消失增加。
