Parturient Paresis in the Cow

Abstract
Serum ionized calcium concentrations (CaF) were determined in 87 Swedish red-and-white cows and 10 Swedish Friesian cows with clinical signs of parturient paresis. All cows were in the week prior to or after parturition. A classification of the severity of hypocalcemia in terms of serum ionized calcium was devised. Eight cows had normal serum ionized calcium concentrations (Cap 1.06–1.26 mmol/1); 15 had slight (CaF 0.80–1.05 mmol/1); 43 a moderate (CaF 0.50–0.79 mmol/1), and 31 asevere (CaF < 0.50 mmol/1) hypocalcemia. All cows were given 8 or 8.3 g of calcium intravenously. Of 8 normocalcemic cows 7 (87.5 %) reached a maximum posttreatment serum ionized calcium concentration > 1.80 mmol/1 (severe hypercalcemia). This was also found in 13 of 15 (86.7 %) slightly hypocalcemic cows and in 31 of 43 (72.1 %) moderately hypocalcemic cows. In the severe hypocalcemia group 14 of 31 (45.2 %) had maximum posttreatment Cap > 1.80 mmol/1). These findings emphazise the need of a rapid pretreatment evaluation of the degree of hypocalcemia. The present study also underlined the difficulty in predicting serum ionized calcium from serum total calcium concentrations.