This study was to conducted to investigate the effect of red clover isoflavones on the health indicated by immune status and blood biochemistry in dairy cows. Sixty-eight healthy Holstein lactating cows were randomly divided into four treatments ( = 17 per treatment) from 5 blocks according to milk yield using a randomized complete block design. No initial differences in parity (2.13 ± 1.21), days in milk (165 ± 21 d), and milk yield (33.93 ± 3.81 kg/d) between groups. Cows were fed the basal diet supplemented with 0, 2, 4, or 8 g/kg red clover extract (RCE) in diet (dry matter based). Feeding, refusal feed weights, and milk yield were recorded three consecutive days in weeks 0, 4, 8, and 12. Blood was collected from the tail vein of the cows on the last day of weeks 4, 8 and 12, 1 h after the morning feeding, and analyzed for hormones, immunoglobulins, inflammatory markers, and markers of liver and kidney activities. The dry matter intake was significantly decreased by 3.7% in the 8 g/kg group ( < 0.05). The fat-corrected milk yield was significantly higher in both of the 2 and 4 g/kg groups ( < 0.01). Plasma estradiol and prolactin showed a quadratic effect with increasing RCE levels, with the highest in the 4 g/kg group ( < 0.05). Plasma tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β levels decreased linearly with increasing dietary RCE levels. Plasma IL-18 levels showed a quadratic effect with increasing dietary RCE levels, with significantly lower levels in both of the 2 and 4 g/kg groups ( < 0.05). Plasma immunoglobulin A and D-lactic acid levels showed a quadratic effect with increasing dietary RCE levels, with significantly higher level in the 4 g/kg group ( < 0.05). The liver function and kidney activity makers were similar ( > 0.05). These results recommend the supplementation of RCE at a level from 2 to 4 g/kg DM.

中文翻译：

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红三叶草异黄酮对泌乳奶牛激素、免疫、炎症和血浆生化的影响

本研究旨在探讨红三叶草异黄酮对奶牛免疫状态和血液生化所显示的健康的影响。采用随机完全区组设计，根据产奶量将 68 头健康荷斯坦泌乳牛随机分为 5 个区组中的 4 个处理组（每个处理组 17 头）。组间胎次（2.13±1.21）、产奶天数（165±21 天）和产奶量（33.93±3.81 kg/d）没有初始差异。奶牛饲喂基础日粮，并在日粮中添加 0、2、4 或 8 g/kg 红三叶草提取物 (RCE)（基于干物质）。在第 0、4、8 和 12 周连续三天记录采食、拒绝饲料重量和产奶量。在第 4、8 和 12 周的最后一天，1 小时后从奶牛的尾静脉采集血液。早上喂食，并分析激素、免疫球蛋白、炎症标记物以及肝脏和肾脏活动标记物。 8 g/kg 组的干物质摄入量显着降低了 3.7%（<0.05）。 2 g/kg 组和 4 g/kg 组的脂肪校正产奶量均显着较高 ( < 0.01)。血浆雌二醇和催乳素随着RCE水平的增加呈二次方效应，在4g/kg组中最高（<0.05）。血浆肿瘤坏死因子 (TNF)-α、白细胞介素 (IL)-6 和 IL-1β 水平随着饮食 RCE 水平的增加而线性下降。血浆 IL-18 水平随着膳食 RCE 水平的增加呈二次方效应，2 和 4 g/kg 组的水平均显着降低 (< 0.05)。血浆免疫球蛋白 A 和 D-乳酸水平随着膳食 RCE 水平的增加呈二次方效应，4 g/kg 组的水平显着较高（< 0.05）。肝功能和肾功能指标相似（>0.05）。这些结果建议补充 RCE 的水平为 2 至 4 g/kg DM。