Ulbrich M, Hoffmann M, Baumeier A
Arch Tierernahr. 1986 Aug;36(8):697-707. doi: 10.1080/17450398609425312.
N balance experiments were carried out with lambs of the ages of 8, 12 and 15 weeks fed with wheat rations with and without 2% urea supplement (N 1 and N 2) as well as with 3% urea and 20% straw (N 3) or with a soya bean meal supplement (N 4). There were no significant differences in the digestibility of the crude nutrients and in per cent of N retention between the individual ages. The straw supplement decreased the digestibility of organic matter, crude protein, crude fibre and NfE. The supplements of soya bean meal or urea increased the crude protein content in comparison to the wheat ration without supplements by 6% in the dry matter and resulted in N intakes 55 ... 60% higher and in 23 ... 38% higher N retention, which was, however, lower in relation to N intake. There were no significant differences with regard to N retention between N 2, N 3 and N 4. Consequently urea supplement to the feed mixture with 14% native crude protein resulted in increased N retention, which was not lower than with a soya bean meal supplement.
对8周龄、12周龄和15周龄的羔羊进行了氮平衡实验，给它们饲喂添加和不添加2%尿素（N1和N2）的小麦日粮，以及添加3%尿素和20%秸秆的日粮（N3）或添加豆粕的日粮（N4）。各年龄段之间粗养分消化率和氮保留百分比没有显著差异。秸秆补充剂降低了有机物、粗蛋白、粗纤维和无氮浸出物的消化率。与未添加补充剂的小麦日粮相比，豆粕或尿素补充剂使干物质中的粗蛋白含量提高了6%，氮摄入量提高了55……60%，氮保留提高了23……38%，然而，相对于氮摄入量，氮保留较低。N2、N3和N4之间在氮保留方面没有显著差异。因此，在含有14%天然粗蛋白的饲料混合物中添加尿素可提高氮保留，且不低于添加豆粕的情况。
