Effects of fenprostalene and estradiol-17 beta benzoate on parturition and retained placenta in dairy cows and heifers.
It was hypothesized that a high dose of estrogen in conjunction with a long-acting PGF2 alpha analog would synchronize parturition within a narrow time frame and reduce the incidence of retained placenta. On d 276 of gestation, 14 animals (9 cows and 5 heifers) per group received a placebo (group A), 1 mg of fenprostalene (group B), 50 mg of estradiol-17 beta benzoate (group C), or both (group D). Treatment with estradiol-17 beta benzoate increased serum concentrations of estradiol-17 beta from 228 pg/ml at treatment to 642 and 683 pg/ml at 24 h posttreatment for groups C and D, respectively. Concentration of estradiol-17 beta in group A increased gradually to 526 pg/ml at 24 h prepartum. Progesterone concentrations were reduced by fenprostalene but not by estradiol-17 beta benzoate. Estradiol-17 beta benzoate did not reduce incidence of retained placenta in animals treated with fenprostalene (group B vs. group D) but tended to reduce incidence in uninduced animals (group A vs. group C). Thus, short-term elevation of estradiol-17 beta to normal prepartum concentrations did not regress the corpus luteum, induce parturition, or reduce incidence of retained placenta. However, elevation of estradiol-17 beta for longer periods might enhance placental separation. Conversely, fenprostalene induced calving approximately 2 d after treatment. In this study, 90% of animals treated with fenprostalene calved within a 20-h period, but with a high incidence of retained placenta.
Rasmussen
F E
FE
Department of Dairy Science, University of Wisconsin, Madison 53706, USA.
Wiltbank
M C
MC
Christensen
J O
JO
Grummer
R R
RR
D000818:Animals; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000517:prevention & control*; D004958:Estradiol / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D007700:Kinetics; D007743:Labor, Obstetric / Q000187:drug effects*; D018457:Placenta, Retained / Q000517:prevention & control / Q000662:veterinary*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology* / Q000627:therapeutic use
D011461:Prostaglandins F, Synthetic; D011374:Progesterone; D004958:Estradiol; C039153:fenprostalene