The objective of this randomized, placebo-controlled, double-blinded field trial was to investigate the effects of oral administration of purple coneflower (Echinacea purpurea L. (EP)) on performance, health and immune parameters in calves.

Calves (n = 27) were enrolled to three groups (9 calves per group): 0.5 g EP/calf per day (ECL), 5 g EP/calf per day (ECH) or placebo. Calves were vaccinated with Bluetongue-Virus (BTV) serotype 4 vaccine to investigate EPs effects on seroconversion. Clinical and performance parameters, inter alia body weight, health and milk intake were recorded for 57 days. Blood samples were analyzed for BTV antibodies and IgG by ELISA, white and red blood cell counts by flow cytometry and mRNA abundance of various inflammatory markers in leukocytes (IL-1β, IL-8, tumor necrosis factor α (TNFα), cyclooxygenase 2 (Cox-2) and prostaglandin E synthase) was studied.

The findings demonstrated no differences between groups regarding performance parameters. In all groups, calves suffered from diarrhea for a minimum of 2 days, but EP reduced the number of diarrhea days by 44% in ECL and increased the body temperature. Interestingly, ECL resulted in an increased number of respiratory disease days during the follow-up period. EP did not change blood cell and IgG counts, whereas eosinophil granulocytes were reduced in ECL. Decreased levels of hemoglobin and hematocrit were found in ECH. Prostaglandin E synthase levels in leukocytes were higher in ECL and ECH, whereas no differences were obtained for IL-1β, IL-8, TNFα and Cox-2. Due to the unexpected occurrence of BTV seropositive calves before the first vaccination, 13 calves were excluded from the evaluation on seroconversion and no statistical analyses could be performed regarding antibody production. BTV-4 antibodies were not produced in 4 placebo-calves, whereas 4 of 5 and 1 of 6 ECL- and ECH-calves produced antibodies.

Further investigations are needed to draw final conclusions on mode of action and efficacy of EP in calves.

这项随机、安慰剂对照、双盲田间试验的目的是研究口服紫锥花（紫锥菊L. (EP)）对犊牛性能、健康和免疫参数的影响。

小牛 ( n  = 27) 被纳入三组（每组 9 头小牛）：每天 0.5 克 EP/小牛 (ECL)、每天 5 克 EP/小牛 (ECH) 或安慰剂。小牛接种了蓝舌病毒 (BTV) 血清型 4 疫苗，以研究 EPs 对血清转化的影响。记录了 57 天的临床和性能参数，尤其是体重、健康和牛奶摄入量。通过ELISA分析血液样本的BTV抗体和IgG，通过流式细胞术分析白细胞和红细胞计数以及白细胞中各种炎症标志物（IL-1β，IL-8，肿瘤坏死因子α（TNFα），环氧合酶2（ Cox-2) 和前列腺素 E 合酶) 进行了研究。

结果表明，各组之间在性能参数方面没有差异。在所有组中，小牛至少腹泻 2 天，但 EP 将 ECL 中的腹泻天数减少了 44%，并提高了体温。有趣的是，ECL 导致随访期间呼吸道疾病天数增加。EP 不改变血细胞和 IgG 计数，而 ECL 中嗜酸性粒细胞减少。在 ECH 中发现血红蛋白和血细胞比容水平降低。ECL 和 ECH 中白细胞中的前列腺素 E 合酶水平较高，而 IL-1β、IL-8、TNFα 和 Cox-2 没有差异。由于在第一次接种疫苗前意外出现了 BTV 血清反应阳性的小牛，13 头小牛被排除在血清转化评估之外，并且无法进行关于抗体产生的统计分析。4 只安慰剂小牛中未产生 BTV-4 抗体，而 5 只中的 4 只和 6 只 ECL 和 ECH 小牛中的 1 只产生了抗体。

需要进一步研究以得出关于 EP 在犊牛中的作用方式和功效的最终结论。