Steroid Hormone Levels in Beef Cows During Pregnancy Terminating in Normal Calving or Abortion and With Single or Multiple Ovulation

Abstract

AorrexouN, V., MATroN, P. eNo Dupoun, J. J. 1978. Steroid

Progesterone Concentration throughout Gestation in Cows with Singleton and Twin Pregnancies.

“…In addition, the result that there was no significant difference between the profiles of untreated singleton and twin-bearing cows is in agreement with some earlier reports [11,15] but contradictory to others [9,14]. Reduced gestational length in twin-bearing cows and also the significantly elevated progesterone concentration found throughout the gestation period in treated cows are comparable with earlier investigations [9,14].…”

“…In general the plasma progesterone secretory profile of untreated singleton cows reported here is consistent with that of several other authors [9][10][11]15] but different from that reported elsewhere [13,14]. In addition, the result that there was no significant difference between the profiles of untreated singleton and twin-bearing cows is in agreement with some earlier reports [11,15] but contradictory to others [9,14].…”

“…Some studies over the past three decades have attempted to characterize the progesterone secretory profiles throughout gestation in the cow with contradictory conclusions. A number of authors [9][10][11][12] found that in singleton pregnancies plasma progesterone concentration was maintained at mid-luteal levels with minimum fluctuations, while others [13,14] reported a significant undulation in plasma progesterone concentration in singleton cows. Data on the effects of fetal number on plasma progesterone are equivocal, thus some workers [11,15] found no difference in plasma progesterone concentration throughout gestation between cows carrying singleton and twin pregnancies, whereas others [9,14] reported significant elevation in plasma progesterone concentration in twin carrying cows compared to singleton cows.…”

“…Disagreements between the above reports could be partly attributable to infrequent and irregular blood sampling protocols. However, these studies do suggest that the peripheral plasma progesterone concentration is influenced by (i) the breed of the dam [10,13], (ii) the number of C.L.s present [9,14], (iii) fetal number [9,14], and (iv) fetal sex [10].…”

Plasma bovine pregnancy-associated glycoprotein concentrations throughout gestation in relationship to fetal number in the cow

“…Although the progesterone concentration is identified commercially as an aid to the diagnosis of pregnancy in the cow, it is not pregnancy-specific and its accuracy is variable (20). In addition, reports on the effect of the number of fetuses being carried on progesterone concentration are conflicting (11,(21)(22)(23), suggesting that bPAG, in common with PSPB (8,12,13) and PSP-60 (7), offers a better serological test for the diagnosis of pregnancy and for distinguishing the number of fetuses being carried. The large individual variation in bPAG concentrations at all stages of gestation in the present study could be attributable to the limited number of animals used.…”