Voigt J, Piatkowski B, Schönhusen U, Kreienbring F, Krawielitzki R, Nagel S
Academy of Agricultural Sciences of the GDR, Research Centre of Animal Production Dummerstorf-Rostock, Division of Animal Nutrition Oskar Kellner.
Arch Tierernahr. 1990 Mar;40(3):245-57. doi: 10.1080/17450399009428400.
The duodenal passages of non-ammonia nitrogen (NAN), amino acid N (AA-N) and microbial N (MN) were measured in seven duodenal fistulated dairy cows (6130 kg FCM/305 d) during lactation receiving 30 different rations similar to those used in dairy practice. The rations consisted of roughage (protein-rich silages, hay) and concentrate mixture (corn, barley, oat) in a ratio of 60:40 on a DM basis or roughage/concentrate mixture/fodder beets in the proportions 60:20:20 or 60:0:40 respectively. N supplements consisted of soya bean meal and peas meal (untreated or treated with formaldehyde in each case), rapeseed meal, fish meal and urea. DM intake varied between 9.6 and 19.1 kg/d, the crude fibre content between 166 and 270 g/kg DM, the crude protein (CP) content between 111 and 184 g/kg DM, the AA content (N basis) of the CP between 51 and 82%, the unfermentable CP content of the CP between 23 and 49% and the organic matter digestibility between 70 and 79%. The duodenal passage of NAN was 24.2 +/- 2.7 g/kg DM intake, 34.9 +/- 4.1 g/kg apparently digestible organic matter (in total tract, DOM), 43.3 +/- 5.5 g/kg apparently digestible carbohydrates or 4.2 +/- 0.5 g/MJ net energy fat, (y +/- s, n = 90). The value measured for AA-N was 16.8 +/- 2.9 g/kg DM intake, and that for RNA-labelled microbial CP was 146 +/- 26 g/kg DOM. NAN passage (g/kg DM intake) correlated more closely with the duodenal digesta flow rate (DFR) (kg digesta/kg DM intake) as an intrinsic animal factor (r = 0.78) and with the rumen content dilution rate (RDR) (passage of microbial-free organic matter at duodenum/kg BW0.75.h) as a ration dependent factor (r = 0.64) than with the UDP fraction (% of ration CP) (r = 0.50) or other ration parameters. It was concluded that the specific effect of protein concentrates in mixed rations on duodenal NAN yields in lactating dairy cows is lower than hitherto assumed. The duodenal NAN yield of a single feedstuff or ration (g/kg DM) in cows is dependent on animal and feeding factors. The DFR could represents a suitable target for breeding activities.
在泌乳期，对7头安装了十二指肠瘘管的奶牛（产奶量为6130千克乳脂校正乳/305天）进行了测量，这些奶牛采食30种不同日粮，类似于奶牛实际生产中使用的日粮。日粮由粗饲料（富含蛋白质的青贮饲料、干草）和精料混合料（玉米、大麦、燕麦）组成，干物质基础上的比例为60:40，或者粗饲料/精料混合料/饲用甜菜的比例分别为60:20:20或60:0:40。氮源补充料包括豆粕和豌豆粕（每种情况均未处理或用甲醛处理）、菜籽粕、鱼粉和尿素。干物质采食量在9.6至19.1千克/天之间，粗纤维含量在166至270克/千克干物质之间，粗蛋白（CP）含量在111至184克/千克干物质之间，CP的氨基酸含量（以氮计）在51%至82%之间，CP中不可发酵CP含量在23%至49%之间，有机物消化率在70%至79%之间。非氨氮（NAN）的十二指肠流通量为24.2±2.7克/千克干物质采食量、34.9±4.1克/千克表观可消化有机物（全消化道，DOM）、43.3±`5.5克/千克表观可消化碳水化合物或4.2±0.5克/兆焦净能脂肪，（y±s，n = 90）。测得的氨基酸氮（AA-N）值为16.8±2.9克/千克干物质采食量，RNA标记的微生物CP值为146±26克/千克DOM。作为内在动物因素，NAN流通量（克/千克干物质采食量）与十二指肠食糜流速（DFR）（千克食糜/千克干物质采食量）的相关性更紧密（r = 0.78），作为日粮相关因素，与瘤胃内容物稀释率（RDR）（十二指肠无微生物有机物流通量/千克体重0.75·小时）的相关性也更紧密（r = 0.64），而与非蛋白氮部分（日粮CP的百分比）（r = 0.50）或其他日粮参数的相关性较弱。得出的结论是，混合日粮中蛋白质浓缩料对泌乳奶牛十二指肠NAN产量的特定影响低于迄今所认为的。奶牛单一饲料或日粮的十二指肠NAN产量（克/千克干物质）取决于动物和饲养因素。DFR可能是育种活动合适的目标。
