Autonomic nervous function evaluated by heart rate variability (HRV) and blood characteristics were compared between Holstein Friesian cows that developed postpartum fever (PF; n = 5) and clinically healthy (CH; n = 6) puerperal cows in this case-control study. A cow was defined as having PF when its rectal temperature rose to ≥39.5°C between 1 and 3 days postpartum. We recorded electrocardiograms during this period using a Holter-type electrocardiograph and applied power spectral analysis of HRV. Comparisons between the groups were analyzed by t test or Mann-Whitney U test, and the relationship between rectal temperature and each parameter was analyzed using multiple regression analysis. Heart rate was higher in PF cows than in CH cows (Mean ± SE, 103.3 ± 2.7 vs. 91.5 ± 1.7 bpm). This result suggested that PF cows had a relatively dominant sympathetic nervous function. Total (44,472 ± 2,301 vs. 55,373 ± 1,997 ms) and low frequency power (24.5 ± 3.8 vs. 39.9 ± 5.3 ms) were lower in PF cows than in CH cows. These findings were possibly caused by a reduction in autonomic nervous function. The total white blood cell count (54.3 ± 5.1 vs. 84.5 ± 6.4 ×10²/μL) and the serum magnesium (2.1 ± 0.1 vs. 2.4 ± 0.1 mg/dL) and iron (81.5 ± 8.0 vs. 134.4 ± 9.1 μg/dL) concentrations were lower and the serum amyloid A concentration (277 ± 33 vs. 149 ± 21 μg/mL) was higher in PF cows than in CH cows. These results imply that more inflammation was present in PF cows than in CH cows. Multiple regression analysis showed that both of low frequency power and concentration of serum iron were associated with rectal temperature. We found differences in changes in hematologic results, biochemical findings, and HRV patterns between PF cows and CH cows.

在该病例对照研究中，比较了由心率变异性（HRV）和血液特征评估的自主神经功能，将发生产后发热（PF; n = 5）的荷斯坦黑白花奶牛与临床健康（CH; n = 6）的产褥牛进行比较。母牛在产后1至3天之间的直肠温度升至≥39.5°C时被定义为患有PF。在此期间，我们使用Holter型心电图仪记录了心电图，并应用了HRV的功率谱分析。通过t检验或Mann-Whitney U分析两组之间的比较测试，并使用多元回归分析分析直肠温度与每个参数之间的关系。PF奶牛的心率高于CH奶牛（平均值±SE，103.3±2.7与91.5±1.7 bpm）。该结果表明PF牛具有相对优势的交感神经功能。与CH奶牛相比，PF奶牛的总数（44,472±2,301 vs. 55,373±1,997 ms）和低频功率（24.5±3.8 vs. 39.9±5.3 ms）要低。这些发现可能是由于自主神经功能下降引起的。白细胞总数（54.3±5.1 vs. 84.5±6.4×10 ²/μL）和血清镁（2.1±0.1 vs. 2.4±0.1 mg / dL）和铁（81.5±8.0 vs. 134.4±9.1μg/ dL）浓度较低，血清淀粉样蛋白A浓度（277±33 vs. PF奶牛的149±21μg/ mL高于CH奶牛。这些结果表明，PF母牛比CH母牛存在更多的炎症。多元回归分析表明，低频能量和血清铁的浓度均与直肠温度有关。我们发现PF奶牛和CH奶牛的血液学结果，生化结果和HRV模式变化存在差异。