Serum calcium concentration in clinically normal multiparous cows after calcium supplementation

Extrapolated serum calcium concentration data for multiparous cows showing no clinical signs of hypocalcemia (N = 33) that were administered either no supplemental calcium (n = 11; dashed green line), IV calcium (n = 11; solid red line), or two oral calcium boluses (n = 11; dotted blue line).

IV calcium supplementation was a single 500-mL dose of a 23% calcium gluconate solution (10.7 g calcium) administered at the time of calving. Oral calcium supplementation was one fat-coated bolus of a mixture of calcium chloride and calcium sulfate administered at calving (43 g of calcium), followed by a second bolus 12 h later.

Note that the first serum sample was taken 1 h after IV calcium supplementation, which is well after the expected peak calcium concentration.

(To convert mg/dL to mmol/L, multiply by 0.25.)