The aim of this study was to evaluate different treatments of postpartum subclinical hypocalcemia in dairy cows with emphasis on PTH response. Twenty four cows with subclinical hypocalcemia (Ca 1.4–2.0 mmol/L), out of 180 Holstein cows tested, were assigned in one of three equal groups: (1) CON received no Ca supplementation, (2) PO-Ca received 1000 mL of oral Ca suspension, immediately after establishing hypocalcemia, and 500 mL of the suspension 12 h after, (3) IV-Ca intravenously received 500 mL of Ca immediately after establishing hypocalcemia. The blood samples were taken up to 48 h after initial treatment for determination of Ca, iP, Mg and PTH concentrations. Urine pH was also evaluated up to 48 h after initial treatment. Compered to CON cows that were hypocalcemic up to the 48 h, Ca concentrations were significantly higher in PO-Ca up to hour 8 and IV-Ca up to hour 24. At first 2 h, PTH concentrations were significantly lower, compared to CON, only in IV-Ca, while at hour 4 PTH concentrations were significantly lower in both treated groups. At hours 24 and 48, PTH concentrations were significantly lower only in PO-Ca compared to CON group. Urine pH values in CON indicate alkalosis and were significantly lower both in PO-Ca and IV-Ca group, up to 12 h and 24 h respectively. In conclusion, both treatments mitigated hypocalcemia in cows, but with significantly different PTH response. Due to adequate PTH response, normocalcemia is established in CON and expected transient hypocalcemia is avoided in IV-Ca cows.

这项研究的目的是评估奶牛产后亚临床低钙血症的不同治疗方法，重点是PTH反应。将180头接受测试的荷斯坦奶牛中的24例亚临床低钙血症（Ca 1.4–2.0 mmol / L）的母牛分为三等分之一：（1）CON不接受钙补充，（2）PO-Ca接受1000 mL在低钙血症发生后立即口服Ca悬浮液，以及在12小时后500 mL悬浮液，（3）在建立低钙血症后立即静脉注射IV-Ca 500 mgCa。初始治疗后长达48小时采集血样，以测定Ca，iP，Mg和PTH的浓度。初始治疗后长达48小时也要评估尿液的pH值。在48小时内低钙血症的CON奶牛中，直到第8小时，PO-Ca和第24小时的IV-Ca中的Ca浓度均显着升高。与CON相比，仅在IV-Ca中，PTH浓度在前2 h显着降低，而在第4小时，PTH浓度显着降低。两组均明显降低。在第24和48小时，仅PO-Ca中的PTH浓度显着低于CON组。CON中的尿液pH值表明碱中毒，PO-Ca和IV-Ca组的尿酸pH值均显着降低，分别长达12小时和24小时。总之，两种治疗均能减轻奶牛的低钙血症，但对PTH的反应却有显着差异。由于足够的PTH反应，在CON中建立了正常血钙，并且在IV-Ca奶牛中避免了预期的短暂性低血钙。仅在IV-Ca中，而在第4小时，两个治疗组的PTH浓度均显着降低。在第24和48小时，仅PO-Ca中的PTH浓度显着低于CON组。CON中的尿液pH值表明碱中毒，PO-Ca和IV-Ca组的尿酸pH值均显着降低，分别长达12小时和24小时。总之，两种治疗均能减轻奶牛的低钙血症，但对PTH的反应却有显着差异。由于足够的PTH反应，在CON中建立了正常血钙，并且在IV-Ca奶牛中避免了预期的短暂性低血钙。仅在IV-Ca中，而在第4小时，两个治疗组的PTH浓度均显着降低。在第24和48小时，仅PO-Ca中的PTH浓度显着低于CON组。CON中的尿液pH值表明碱中毒，PO-Ca和IV-Ca组的尿酸pH值均显着降低，分别长达12小时和24小时。总之，两种治疗均能减轻奶牛的低钙血症，但对PTH的反应却有显着差异。由于足够的PTH反应，在CON中建立了正常血钙，并且在IV-Ca奶牛中避免了预期的短暂性低血钙。CON中的尿液pH值表明碱中毒，PO-Ca和IV-Ca组的尿酸pH值均显着降低，分别长达12小时和24小时。总之，两种治疗均能减轻奶牛的低钙血症，但对PTH的反应却有显着差异。由于足够的PTH反应，在CON中建立了正常血钙，并且在IV-Ca奶牛中避免了预期的短暂性低血钙。CON中的尿液pH值表明碱中毒，PO-Ca和IV-Ca组的尿酸pH值均显着降低，分别长达12小时和24小时。总之，两种治疗均能减轻奶牛的低血钙症，但对PTH的反应却明显不同。由于足够的PTH反应，在CON中建立了正常血钙，并且在IV-Ca奶牛中避免了预期的短暂性低血钙。