Alterations in the systemic acid-base status and blood gas dynamics during progressive hypocalcaemia in cow calves.

Hypocalcaemia, induced in cow calves by slow infusion of Na2EDTA for 6 hr, led to biphasic changes in acid-base status. Decrease in ionized plasma Ca2+ concentration upto 0.82 +/- 0.06 mmole 1(-1) was associated with metabolic alkalosis. Further decrease in ionized plasma Ca2+ concentration (0.61 +/- 0.09 mmole 1(-1)) led to metabolic acidosis, superimposed by a respiratory component. There was significant decrease in oxygen tension and saturation of arterial blood as well as impaired uptake of oxygen by peripheral tissues and pulmonary blood.