<abstract xmlns="http://www.w3.org/1999/xhtml">
<sec id="j_jvetres-2021-0053_s_005">
<h3>Introduction</h3>
<p>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.</p></sec>
<sec id="j_jvetres-2021-0053_s_006">
<h3>Material and Methods</h3>
<p>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.</p></sec>
<sec id="j_jvetres-2021-0053_s_007">
<h3>Results</h3>
<p>In hypercalcaemic cows, both blood and urine calcium levels were significantly increased at 8 h compared to those at 0 h (P &lt; 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 (<italic>r</italic> = 0.781, P &lt; 0.001) rather than that in partial pressure of CO<sub>2</sub> (<italic>r</italic> = 0.085, P = 0.424).</p></sec>
<sec id="j_jvetres-2021-0053_s_008">
<h3>Conclusion</h3>
<p>Hypercalcaemia induced a spontaneous change in blood pH through the bicarbonate buffer system and this system may be a maintainer of calcium homeostasis.</p></sec>
</abstract>

Introduction
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.

Material and Methods
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.

Results
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 (r = 0.781, P < 0.001) rather than that in partial pressure of CO2 (r = 0.085, P = 0.424).

Conclusion
Hypercalcaemia induced a spontaneous change in blood pH through the bicarbonate buffer system and this system may be a maintainer of calcium homeostasis.

Spontaneous alteration of blood pH by a bicarbonate buffer system during experimental hypercalcaemia in cows

Journal of Veterinary Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Introduction
Maintaining mineral homeostasis as well as the secretion and metabolism of mineralotropic hormones is important for healthy of periparturient...

Spontaneous alteration of blood pH by a bicarbonate buffer system during experimental hypercalcaemia in cows

Article Category: Review article

Publié en ligne: 01 oct. 2021

Pages: 539 - 543

Reçu: 17 mars 2021

Accepté: 23 sept. 2021

DOI: https://doi.org/10.2478/jvetres-2021-0053

Mots clés
calcium, blood pH, cattle, hypercalcaemia, bicarbonate buffer system

© 2021 Y. Ro et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Spontaneous alteration of blood pH by a bicarbonate buffer system during experimental hypercalcaemia in cows

Article Category: Review article

Publié en ligne: 01 oct. 2021

Pages: 539 - 543

Reçu: 17 mars 2021

Accepté: 23 sept. 2021

DOI: https://doi.org/10.2478/jvetres-2021-0053

Mots cléscalcium, blood pH, cattle, hypercalcaemia, bicarbonate buffer system

© 2021 Y. Ro et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Mots clés
calcium, blood pH, cattle, hypercalcaemia, bicarbonate buffer system