Glenn B P, Varga G A, Huntington G B, Waldo D R
U.S. Department of Agriculture, Beltsville, MD 20705.
J Anim Sci. 1989 Feb;67(2):513-28. doi: 10.2527/jas1989.672513x.
Formaldehyde- and formic acid-treated alfalfa or orchardgrass silage were fed at 65 and 90 g DM/kg BW.75.d) to growing Holstein steers (209 +/- SE = 35 kg) fitted with permanent ruminal and duodenal cannulas in a 4 x 4 latin square. Alfalfa had higher (P less than .01) concentrations of cell solubles, total N and rumen-soluble N than did orchardgrass. Digestible energy (Mcal/d), total N and soluble N intake (g/d) were higher (P less than .05) for steers fed alfalfa than for those fed orchardgrass. Total duodenal OM, DM, NDF, N and non-NH3-N flows were greater (P less than .001) for steers fed alfalfa than for those fed orchardgrass and were greater (P less than .001) at high vs low intake. Duodenal bacterial N flow (g/d) was greater (P less than .001) for steers fed alfalfa than for those fed orchardgrass, and bacterial N synthesis (g/kg DM truly digested in the rumen) was 58 and 32, respectively (P less than .001). Ruminal concentrations of NH3-N (P less than .001) and VFA (P less than .05) were greater for steers fed alfalfa than for those fed orchardgrass. Total tract DM, energy and N digestibilities were higher (P less than .05) for steers fed alfalfa vs orchardgrass, whereas total tract NDF digestibility was lower (P less than .01). Tissue N retention tended to be greater (P less than .1) for steers fed alfalfa than for those fed orchardgrass. Regression analysis indicated that duodenal non-NH3-N flow was related to intake of metabolizable energy and soluble N (R2 = .939). Improved performance and higher efficiency of use of ME for tissue gain by steers fed alfalfa rather than orchardgrass is related to lower ruminal acetate:propionate, higher microbial efficiency and greater duodenal DM and N flows.
将经甲醛和甲酸处理的苜蓿或果园草青贮料以65和90克干物质/千克体重.75.d)的量投喂给体重209±标准误 = 35千克、装有永久性瘤胃和十二指肠瘘管的生长阶段荷斯坦阉牛，采用4×4拉丁方设计。苜蓿的细胞可溶物、总氮和瘤胃可溶氮浓度高于果园草（P <.01）。饲喂苜蓿的阉牛的可消化能量（兆卡/天）、总氮和可溶氮摄入量（克/天）高于饲喂果园草的阉牛（P <.05）。饲喂苜蓿的阉牛的十二指肠总有机物质、干物质、中性洗涤纤维、氮和非氨氮流量大于饲喂果园草的阉牛（P <.001），且高摄入量时大于低摄入量（P <.001）。饲喂苜蓿的阉牛的十二指肠细菌氮流量（克/天）大于饲喂果园草的阉牛（P <.001），细菌氮合成（克/瘤胃中真正消化的千克干物质）分别为58和32（P <.001）。饲喂苜蓿的阉牛的瘤胃氨氮浓度（P <.001）和挥发性脂肪酸浓度（P <.05）高于饲喂果园草的阉牛。饲喂苜蓿的阉牛的全消化道干物质、能量和氮消化率高于饲喂果园草的阉牛（P <.05），而全消化道中性洗涤纤维消化率较低（P <.01）。饲喂苜蓿的阉牛的组织氮保留量倾向于高于饲喂果园草的阉牛（P <.1）。回归分析表明，十二指肠非氨氮流量与代谢能和可溶氮摄入量相关（R2 =.939）。与饲喂果园草相比，饲喂苜蓿的阉牛性能改善且利用代谢能促进组织生长的效率更高，这与瘤胃乙酸:丙酸比例较低、微生物效率较高以及十二指肠干物质和氮流量较大有关。
