PDF(Pubmed)
Abstract：
The use of goats for meat production faces challenges from environmental and nutritional factors. Urea is an affordable non-protein nitrogen source commonly utilized in ruminant nutrition. The objective of this study was to investigate nitrogen utilization in goats fed low-quality hay supplemented with molasses blocks containing urea. Twenty Anglo-Nubian doelings were individually housed in metabolic cages and provided with chopped Buffelgrass (Cenchrus ciliaris) hay ad libitum. Goats were randomly assigned to four urea levels (0, 2, 4, and 6%; n = 5 per treatment) in molasses blocks for a duration of 30 days. A negative nitrogen balance (-2.458 g/day) was observed in doelings consuming blocks without urea, compared with a positive balance (0.895 g/d) for those consuming the 6% urea blocks. Block nitrogen intake significantly increased with urea level, but urea supplementation did not affect dry matter (DM) or neutral detergent fiber (NDFom) intake or digestibility. A minimum crude protein (CP) requirement of 8% for maintenance in doelings consuming low-quality forage with a urea-based supplement was determined through regression analysis between CP intake (% of DM) and N balance (r2 = 0.479; p < 0.002). The value of 8% of CP obtained in this study is similar to several previous studies reported in the literature, but in this case, the increments in CP came exclusively from urea. In this study, increasing the urea content of molasses blocks up to 6% significantly increased nitrogen intake, retention, and balance in goats. These results contribute to a better understanding of nitrogen utilization in goats fed low-quality hay with urea supplementation.
摘要：
使用山羊进行肉类生产面临环境和营养因素的挑战。尿素是反刍动物营养中常用的负担得起的非蛋白质氮源。这项研究的目的是研究饲喂低质量干草的山羊中的氮利用情况，该干草补充了含尿素的糖蜜块。将20个盎格鲁-努比亚土墩分别安置在代谢笼中，并随意提供切碎的Buffelgrass（Cenchrusciliaris）干草。山羊被随机分配到糖蜜块中的四种尿素水平（0、2、4和6％；每次处理n=5），持续30天。在不含尿素的磨牙块中观察到负氮平衡（-2.458g/天），与那些消耗6%尿素块的人的正平衡(0.895g/d)相比。块氮的摄入量随尿素水平显著增加，但是补充尿素不会影响干物质（DM）或中性洗涤剂纤维（NDFom）的摄入量或消化率。通过对CP摄入量（DM的％）和N平衡（r2=0.479；p<0.002）之间的回归分析，确定了使用尿素补充剂的劣质牧草维持的最低粗蛋白（CP）要求为8％。在这项研究中获得的CP的8％的值与文献中报道的一些先前的研究相似，但在这种情况下,CP的增量完全来自尿素。在这项研究中,增加糖蜜的尿素含量高达6％，显着增加氮摄入量，保留,和平衡山羊。这些结果有助于更好地了解饲喂低质量干草并补充尿素的山羊中的氮利用。
