Reproductive effects of estradiol cypionate in postparturient dairy cows.
OBJECTIVE
To determine the effects of estradiol cypionate (ECP) on measures of reproductive efficiency in postparturient dairy cows.


METHODS
Randomized clinical trial.


METHODS
273 cows in a single herd in California.


METHODS
Twenty-four hours after parturition, 122 cows were treated with ECP (4 mg, IM); the remaining 151 cows were untreated controls. Percentages of cattle with abnormal findings during uterine palpation 27 to 40 days after parturition were compared between groups, along with days to first artificial insemination (AI), percentages of cows that were not pregnant after the first AI, and days to pregnancy.


RESULTS
Treatment with ECP did not have a significant effect on whether results of uterine palpation 27 to 40 days after parturition were abnormal, days to first AI, or odds that a cow would be pregnant after the first AI. Treatment with ECP appeared to have a negative effect on days to pregnancy (hazard ratio, 0.72)


CONCLUSIONS
Results suggest that prophylactic administration of ECP during the early postparturient period in dairy cows did not have measurable beneficial effects on reproductive efficiency.
Wagner
D C
DC
Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis 95616, USA.
BonDurant
R H
RH
Sischo
W M
WM
D000818:Animals; D002417:Cattle / Q000502:physiology*; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary*; D010062:Ovulation Induction / Q000662:veterinary*; D049590:Postpartum Period; D011247:Pregnancy; D012098:Reproduction / Q000187:drug effects*; D013997:Time Factors
D004958:Estradiol; C007630:estradiol 17 beta-cypionate