ARE THERE EFFECTS OF DERIVATIVES OF VITAMIN-D GIVEN TO HIGHLY PREGNANT DAIRY-COWS IN THE PREVENTION OF PARTURIENT PARESIS ON THE MATERNAL-FETAL MINERAL RELATIONSHIPS

Intramuscular injection of 1alpha-hydroxyvitamin D3 (with or without 2 5-hydroxyvitamin D3) to highly pregnant dairy cows caused a significan t increase of ionized calcium in blood and of total calcium and inorga nic phosphate with a concomitant decrease of magnesium in blood plasma 3,5 +/- 1,9 days later (resp. 12 - 48 h a.p.). This brought about a h igher Ca level at parturition preventing parturient paresis. The chang es of maternal mineral and vitamin D status had no effect on the miner al concentrations of blood in newborn calves. However, the increase in calcium and phosphate concentrations in maternal blood after injectio n was accompanied by an increase of the minerals in the amniotic fluid reflecting their strong reciprocal exchange. On the other hand, the c omposition of allantoic fluid showed no significant changes. Therefore , analysis of both fetal fluids does not refer to disorders of fetal m ineral metabolism. As a consequence, there seems to be no potential ri sk of intoxication after a prepartal injection of the substances to th e mother for their offspring.