Drackley J K, Elliott J P
Department of Animal Sciences, University of Illinois, Urbana 61801.
J Dairy Sci. 1993 Jan;76(1):183-96. doi: 10.3168/jds.S0022-0302(93)77337-3.
Four Holstein cows (84 DIM) were used in a 4 x 4 Latin square with 21-d periods to determine the effects of increasing amounts of partially hydrogenated tallow in the diet. Tallow replaced ground shelled corn at 0, 2, 4, or 6% of total DM; diets contained 3.3, 5.1, 7.3, and 9.0% total fatty acids. Feces and urine were collected during d 16 to 21 of each period. Milk production (31.1, 31.7, 34.6, and 32.8 kg/d), milk fat content, and DMI (21.2, 20.8, 22.2, and 21.5 kg/d) were not significantly different among diets supplemented with 0, 2, 4, or 6% tallow. Tallow decreased contents of CP and SNF in milk but increased production of NPN. Percentages of short- and medium-chain fatty acids in milk fat decreased linearly, whereas percentage of C18:1 increased with increasing dietary tallow. Ruminal pH, concentrations of total VFA and NH3 N, molar percentages of VFA, and acetate to propionate ratio did not differ among treatments. Total tract apparent digestibilities of DM, OM, NDF, ADF, cellulose, hemicellulose, ether extract, energy, and soluble residue did not differ among treatments. Digestibility of total fatty acids decreased in diets containing tallow. Increasing tallow linearly increased N apparently absorbed, but utilization of energy and N was not significantly different among treatments. Partially hydrogenated tallow included at 6% or less of dietary DM did not adversely affect DMI, digestibilities, or ruminal fermentation characteristics.
选用4头荷斯坦奶牛（产犊后84天），采用4×4拉丁方设计，试验期为21天，以确定日粮中添加不同量部分氢化牛脂的影响。牛脂替代粉碎去壳玉米的量分别为总干物质的0%、2%、4%或6%；日粮中总脂肪酸含量分别为3.3%、5.1%、7.3%和9.0%。在每个试验期的第16至21天收集粪便和尿液。添加0%、2%、4%或6%牛脂的日粮间，产奶量（分别为31.1、31.7、34.6和32.8千克/天）、乳脂率和干物质采食量（分别为21.2、20.8、22.2和21.5千克/天）无显著差异。牛脂降低了乳中粗蛋白和非脂固形物含量，但增加了非蛋白氮的产量。乳脂中短链和中链脂肪酸的百分比呈线性下降，而C18:1的百分比随日粮牛脂添加量的增加而增加。各处理间瘤胃pH值、总挥发性脂肪酸和氨态氮浓度、挥发性脂肪酸的摩尔百分比以及乙酸与丙酸比值无差异。各处理间干物质、有机物、中性洗涤纤维、酸性洗涤纤维、纤维素、半纤维素、醚提取物、能量和可溶性残渣的全肠道表观消化率无差异。含牛脂日粮中总脂肪酸的消化率降低。牛脂添加量的增加使氮的表观吸收量呈线性增加，但各处理间能量和氮的利用率无显著差异。日粮干物质中部分氢化牛脂添加量在6%及以下时，对干物质采食量、消化率或瘤胃发酵特性无不利影响。
