Rauch Rainer, Nichols Kelly, de Carvalho Isabela P C, Daniel Jean-Baptiste, Martín-Tereso Javier, Dijkstra Jan
Trouw Nutrition R&D, Amersfoort, The Netherlands.
Animal Nutrition Group, Wageningen University and Research, Wageningen, The Netherlands.
J Anim Physiol Anim Nutr (Berl). 2025 Jan;109(1):64-75. doi: 10.1111/jpn.14034. Epub 2024 Aug 13.
We expected mitigation of the hypophagic effects of urea (U) with a coated urea (CU) product that aimed to partially shift urea supply to the post-ruminal gastrointestinal tract. Ruminal release and post-ruminal digestibility of CU was evaluated in vitro, followed by a randomised complete block experiment (54 Holstein-Friesian cows; 177 ± 72 days in milk). Soybean meal (SBM) was partially (PR) or fully (FR) replaced on an isonitrogenous basis by beet pulp and U or CU. Urea sources were included at 12 (U-PR, CU-PR) and 19 (U-FR, CU-FR) g/kg dietary dry matter (DM). Hypophagic effects were similar for U-PR and CU-PR (-11% vs. -7%), and for U-FR and CU-FR (-13% vs. -12%) compared with SBM (average 25.8 kg DM intake/d). Compared with SBM, U-PR and CU-PR reduced yields of milk (-8%) and protein (-12%), U-PR reduced yield of fat (-9%) and fat- and protein-corrected-milk (FPCM; -9%), and CU-PR tended to reduce FPCM yield (-5%). Compared with SBM, U-FR and CU-FR respectively reduced yields of milk (-21%, -22%), protein (-25%, -26%), fat (both -14%), lactose (-20%, -21%), and FPCM (-17%, -19%), and lowered N (-15%, -12%) and feed (-8%, trend, -9%) efficiency. Human-edible protein efficiency approximately doubled with U-PR and CU-PR and approximately tripled with U-FR and CU-FR compared with SBM. Milk composition and plasma urea concentration were similar between U and CU, except for a trend for a greater plasma urea concentration with U-PR compared with CU-PR. Dry matter intake patterns differed for CU-PR compared with U-PR and for CU-FR compared with U-FR, suggesting effects of urea release rate or location on feeding behaviour. Overall, replacing SBM with U or CU reduced DM intake and milk production and affected nutrient efficiencies. Coated urea influenced DM intake pattern but did not affect total DM intake or milk production compared with U.
我们期望一种包膜尿素（CU）产品能减轻尿素（U）的厌食效应，该产品旨在将部分尿素供应转移至瘤胃后胃肠道。在体外评估了CU的瘤胃释放和瘤胃后消化率，随后进行了一项随机完全区组试验（54头荷斯坦-弗里生奶牛；产奶177±72天）。以等氮为基础，用甜菜粕和U或CU部分（PR）或完全（FR）替代豆粕（SBM）。尿素来源以12（U-PR、CU-PR）和19（U-FR、CU-FR）克/千克日粮干物质（DM）的量添加。与SBM（平均日采食量25.8千克DM）相比，U-PR和CU-PR的厌食效应相似（-11%对-7%），U-FR和CU-FR的厌食效应也相似（-13%对-12%）。与SBM相比，U-PR和CU-PR降低了牛奶产量（-8%）和蛋白质产量（-12%），U-PR降低了脂肪产量（-9%）和脂肪及蛋白质校正乳（FPCM；-9%）产量，CU-PR有降低FPCM产量的趋势（-5%）。与SBM相比，U-FR和CU-FR分别降低了牛奶产量（-21%，-22%）、蛋白质产量（-25%，-26%）、脂肪产量（均为-14%）、乳糖产量（-20%，-21%）和FPCM产量（-17%，-19%），并降低了氮（-15%，-12%）和饲料（-8%，趋势，-9%）效率。与SBM相比，U-PR和CU-PR的人类可食用蛋白质效率约提高一倍，U-FR和CU-FR约提高两倍。U和CU之间的牛奶成分和血浆尿素浓度相似，但与CU-PR相比，U-PR的血浆尿素浓度有升高趋势。与U-PR相比，CU-PR的干物质采食模式不同，与U-FR相比，CU-FR的干物质采食模式也不同，这表明尿素释放速率或位置对采食行为有影响。总体而言，用U或CU替代SBM会降低干物质采食量和牛奶产量，并影响养分效率。与U相比，包膜尿素影响干物质采食模式，但不影响总干物质采食量或牛奶产量。
