Serum calcium concentration, multiparous cows, calcium supplementation

Figure showing extrapolated serum calcium concentration data for multiparous cows (n=33) administered no supplemental calcium (n=11), IV calcium (n=11), or 2 oral calcium boluses (n=11). IV calcium supplementation was a single dose of 500 mL 23% calcium gluconate (10.7 g calcium) administered at the time of calving.

Note that the first serum sample was taken 1 hour after IV calcium supplementation, which is well after the expected peak calcium concentration. Oral calcium supplementation was one fat-coated bolus of a mixture of CaCl2 and CaSO4 administered at calving (43 g of calcium) followed by a second bolus 12 hours later.