Ro Younghye, Choi Woojae, Hong Leegon, Kim Eunkyung, Choe Eunhui, Kim Danil
Department of Farm Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 08826, Korea.
Farm Animal Clinical Training and Research Center, Institutes of Green-Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Korea.
J Vet Res. 2021 Oct 1;65(4):539-543. doi: 10.2478/jvetres-2021-0053. eCollection 2021 Dec.
Maintaining mineral homeostasis as well as the secretion and metabolism of mineralotropic hormones is important for healthy of periparturient dairy cows. To increase the activity of mineralotropic hormones, blood pH can be adjusted. The purpose of this study was to investigate changes in blood pH and the mechanism of action of this change in induced hypercalcaemic cows.
Six non-lactating Holstein cows were used in a 2 × 2 crossover design. To induce hypercalcaemia, calcium borogluconate was administered subcutaneously to experimental cows and normal saline was administered subcutaneously to control cows. Blood and urine samples were collected serially after administration. Whole blood without any anticoagulant was processed with a portable blood gas analyser. Plasma concentration and urinary excretion of calcium were measured.
In hypercalcaemic cows, both blood and urine calcium levels were significantly increased at 8 h compared to those at 0 h (P < 0.05), and a spontaneous increase in blood pH was also observed. The calcium concentration in plasma was highest at 2 h after administration (3.02 ± 0.27 mmol/L). The change in pH correlated with that in bicarbonate ( = 0.781, P < 0.001) rather than that in partial pressure of CO ( = 0.085, P = 0.424).
Hypercalcaemia induced a spontaneous change in blood pH through the bicarbonate buffer system and this system may be a maintainer of calcium homeostasis.
维持矿物质稳态以及矿物质代谢激素的分泌和代谢对于围产期奶牛的健康至关重要。为了增加矿物质代谢激素的活性，可以调节血液pH值。本研究的目的是调查高钙血症奶牛血液pH值的变化及其诱导这种变化的作用机制。
采用2×2交叉设计，使用6头非泌乳荷斯坦奶牛。为诱导高钙血症，对实验奶牛皮下注射葡萄糖酸硼钙，对对照奶牛皮下注射生理盐水。给药后连续采集血液和尿液样本。使用便携式血气分析仪对未添加任何抗凝剂的全血进行处理。测量血浆钙浓度和尿钙排泄量。
在高钙血症奶牛中，与0小时相比，8小时时血液和尿液钙水平均显著升高（P<0.05），同时还观察到血液pH值自发升高。给药后2小时血浆钙浓度最高（3.02±0.27 mmol/L）。pH值的变化与碳酸氢盐的变化相关（r=0.781，P<0.001），而与二氧化碳分压的变化无关（r=0.085，P=0.424）。
高钙血症通过碳酸氢盐缓冲系统诱导血液pH值自发变化，该系统可能是钙稳态的维持者。
