The experiment was designed to study the use of rambutan (Nephelium lappaceum) fruit peel powder (RP) with urea (U) supplementation on rumen fermentation, digestibility, methane (CH₄) production, milk production and composition in lactating dairy cows. Four Holstein crossbred lactating dairy cows, with starting liveweight of 450 ± 15 kg with 130 ± 10 DIM (days-in-milk), were randomly allocated to respective treatments: without supplementation (control; T1), supplementation of urea (U) at 90 g/hd/day (T2), supplementation of RP at 450 g/hd/day (T3) and supplementation of RPU (RP at 450 g/hd/day and U 90 g/hd/day) (T4), respectively, using a 4 × 4 Latin square design. The results showed that the U, RP and RPU supplementation did not change feed intakes (p > 0.05) and digestibilities of DM and OM were similar. However, digestibilities of CP and NDF were increased in the U and RPU groups (p < 0.05). Acetate production was decreased, while propionate production was dramatically increased (p < 0.05) in both the RP and RPU groups respectively. Notably, the ratio of C₂:C₃, protozoal population and CH₄ production was reduced in both the RP and RPU groups. In addition, nitrogen intake and nitrogen excretion were significantly higher while nitrogen retention was increased in the U and RPU groups. Allantoin excretion and absorption, microbial protein synthesis and efficiency of microbial N supply were increased in the U and RPU supplementation groups (p < 0.05). Furthermore, milk yield, milk fat and total solids were significantly enhanced in the U and RPU groups (p < 0.05). Moreover, the 3.5% FCM was increased (p < 0.05) while milk protein, lactose, solids-not-fat and milk urea nitrogen were not altered (p > 0.05). Supplementation of either U or RPU significantly improved fibre digestibilities, rumen fermentation, microbial protein synthesis, reduced protozoal population, mitigated CH₄ production and enhanced milk yield and milk composition.

中文翻译：

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红毛丹果皮粉和尿素降低泌乳奶牛瘤胃甲烷和促进发酵

本试验旨在研究红毛丹（Nephelium lappaceum）果皮粉（RP）和尿素（U）补充剂对泌乳奶牛瘤胃发酵、消化率、甲烷（CH ₄）产量、产奶量和成分的影响。四头荷斯坦杂交泌乳奶牛，起始活重为 450 ± 15 kg，DIM 为 130 ± 10 DIM（产奶天数），随机分配到各自的处理组：不补充（对照；T1），补充尿素（U）在90 g/hd/天 (T2)，分别补充 450 g/hd/天的 RP (T3) 和补充 RPU（RP 450 g/hd/天和 U 90 g/hd/天）（T4） ，使用 4 × 4 拉丁方设计。结果表明，添加 U、RP 和 RPU 并没有改变采食量（p > 0.05) 并且 DM 和 OM 的消化率相似。然而，U 和 RPU 组中 CP 和 NDF 的消化率增加（p  < 0.05）。 在 RP 和 RPU 组中，乙酸盐产量减少，而丙酸盐产量分别显着增加（p < 0.05）。值得注意的是，C ₂ :C ₃、原生动物种群和CH ₄产量的比率在RP 和RPU 组中均降低。此外，U 和 RPU 组的氮摄入量和氮排泄量显着增加，而氮保留量增加。尿囊素排泄和吸收、微生物蛋白质合成和微生物氮供应效率在 U 和 RPU 补充组中增加（p < 0.05)。此外，U 组和 RPU 组的产奶量、乳脂和总固体含量显着提高（p  < 0.05）。此外，3.5% 的 FCM 增加（p  < 0.05），而牛奶蛋白质、乳糖、非脂肪固体和牛奶尿素氮没有改变（p  > 0.05）。补充 U 或 RPU 可显着改善纤维消化率、瘤胃发酵、微生物蛋白质合成、减少原生动物种群、减少 CH ₄产生并提高牛奶产量和牛奶成分。