Effects of Administered Vitamin D₃ on Calcium Metabolism in Cows before and after Parturition

Abstract

The pupose of this study was to validate effects of administered vitamin D₃ on Ca metabolism o cows during pre- and post-parturition. Ten Holstein-Friesian cows were divided into two groups, a control group of six and an experimental group of four. This group was injected intramuscularly with 10 million I.U. of vitamin D₃ 2-6 days before parturition.
The amount of apparent Ca absorption was significantly larger in the experimental group than in the control at parturition and 1-2 days after parturition. The mean amount of milk Ca secretion was smaller in that group than in the control. The amount of Ca retention was significantly larger in the experimental group than in the control at parturition and 1 day after parturition. It was suggested that this increase in Ca retention might have resulted from the increase in Ca absorption from the intestinal tract and the decrease in milk Ca secretion.