PERIPHERAL PLASMA LEVELS OF OESTRONE AND PROGESTERONE IN PREGNANT COWS TREATED WITH DEXAMETHASONE

Abstract

ABSTRACT Eight pregnant cows of the Swedish Red and White Breed were used. Four cows at 248–250 days of pregnancy received 10 or 20 mg of dexamethasone1) intramuscularly and a second dose equal to the first 3 to 6 days later. Two cows at day 75 and two cows at days 147 and 150 of pregnancy received daily injections of 40 mg of dexamethasone for 7 to 12 days. All late pregnant cows delivered living calves 12 to 68 hours after the second injection. One cow at day 150 of pregnancy aborted on the 6th day from the start of treatment. In all the other cows dead foetuses were found. An increase in oestrone and a decrease in progesterone in peripheral blood plasma were observed in all late pregnant cows after the dexamethasone treatment. The increase in oestrone preceded the decrease in progesterone. The cow pregnant for 150 days which aborted showed decreased plasma levels of progesterone before abortion. No pronounced changes in the levels of progesterone were observed in the other three early pregnant cows. The peripheral plasma levels of oestrone showed no increase in any of the early and mid-term pregnant cows.