Hypocalcemic Properties of Parturient Bovine Plasma

Abstract

Summary Plasma obtained from nonlactating preparturient cows, parturient cows, and lactating cows was transfused into yearling heifers and the subsequent changes in their plasma calcium and inorganic phosphorus levels were followed for 72 hr. When plasma from nonlactating cows was transfused, the average plasma calcium level of the recipient heifers was decreased by 1 mg/100 ml for 7 hr. Plasma transfused from parturient cows also decreased the plasma calcium level of the recipient heifers by 1 mg/100 ml, but the depressed level persisted for 18 hr. When plasma from lactating cows was administered, the average plasma calcium level of the heifers was not significantly altered except at 12 hr after transfusion, when an increase of 0.4 mg/100 ml was observed. The plasma inorganic phosphorus level of the heifers varied from 6.2–8.3 mg/100 ml, but was not altered significantly from the starting level by transfusions from any of the groups of cows. The data suggest the presence of a factor which depresses the level of calcium in the blood or which suppresses calcium mobilization from bone.