Equine chorionic gonadotropin administration after insemination affects luteal function and pregnancy establishment in postpartum anestrous beef cows

Two experiments were conducted with the aim of determining the effect of equine chorionic gonadotropin (eCG) administration on day 14 after insemination on ovarian response and pregnancy establishment in postpartum anestrous beef cows. In both experiments, cows were subjected to a progesterone- and...

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Bibliographic Details
Published in:Domestic animal endocrinology 2018-01, Vol.62, p.24-31
Main Authors: Núñez-Olivera, R., de Castro, T., Bó, G.A., Piaggio, J., Menchaca, A.
Format: Article
Language:English
Subjects:
Anestrus
Animals
Cattle - physiology
Corpus Luteum - drug effects
Corpus Luteum - physiology
Critical period
Embryonic losses
Estrus Synchronization - physiology
Female
Gestation
Gonadotropins, Equine - administration & dosage
Gonadotropins, Equine - pharmacology
Insemination, Artificial - veterinary
PMSG
Postpartum Period
Pregnancy
Pregnancy, Animal - drug effects
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Summary:Two experiments were conducted with the aim of determining the effect of equine chorionic gonadotropin (eCG) administration on day 14 after insemination on ovarian response and pregnancy establishment in postpartum anestrous beef cows. In both experiments, cows were subjected to a progesterone- and estradiol-based treatment for fixed-time artificial insemination (FTAI) and were randomly allocated into 4 groups to receive or not receive eCG (400 IU) at the time of device removal and/or at 14 d after FTAI. In experiment 1, from day 14 to 22, daily ultrasonographic determinations were performed to monitor ovarian dynamics, and blood was collected to determine hormone concentrations in 60 cows. In experiment 2, confirmation of pregnancy was performed at 30 and 60 d after FTAI in 1,060 anestrous cows assigned to the same experimental design. Cows that received eCG on day 14 after FTAI showed increases in corpus luteum area (P < 0.01), follicle diameter (P < 0.05), serum progesterone concentrations (P < 0.01), and estradiol-17β concentrations (P < 0.01), compared with cows that did not receive eCG on day 14. Pregnancy rate on day 30 was greater in those cows that received both eCG treatments (ie, at device removal and 14 d after insemination) than in those that did not receive eCG treatment (P < 0.05). In conclusion, eCG administered on day 14 after FTAI increases serum progesterone concentrations during the critical period of pregnancy in anestrous cows, and this second eCG treatment seems to have a positive effect on achieving pregnancy. •We studied the effect of eCG administered 14 d after insemination in cattle.•Cows that received eCG increased CL size and serum progesterone concentrations.•Also increased estradiol concentrations 2 d after treatment.•The treatment improved pregnancy establishment in anestrous beef cows.
ISSN:0739-7240
1879-0054
DOI:10.1016/j.domaniend.2017.08.003