Diminished Hypercalcemic Response to Parathyroid Extract in Prepartum Cows

Abstract

Parathyroid extract was administered to five cows shortly before and after parturition in addition to postpartal injections only in two other cows. Plasma calcium concentration was measured in each experiment before and after administration of the extract. The postpartal response to parathyroid extract, as assessed by elevation of plasma calcium concentration, occurred more consistently and appeared to be greater than that observed before parturition. The possible mechanisms responsible for diminished prepartal responsiveness and its potential significance in relation to parturient paresis are discussed. © 1973, American Dairy Science Association. All rights reserved.