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Published on: September 19, 2025
Lecirelin-cloprostenol: A single-dose compounding formulation for ovulation induction in beef cows
Luiz Francisco Machado Pfeifer1, Cintia Batista Hurtado2, Vanessa Lemos de Souza3
1Embrapa Rondonia, Brazilian Agricultural Research Corporation, Porto Velho, RO, Brazil.
Theriogenology
|August 13, 2026
Summary
A new Lecirelin-Cloprostenol (GPG) combination improved ovulation synchrony in timed artificial insemination (TAI) protocols for cattle. While GPG enhanced ovulation timing, its impact on pregnancy per artificial insemination (P/AI) was minimal in this study.
Area of Science:
- Veterinary Medicine
- Reproductive Biology
- Animal Science
Background:
- Gonadotropin-releasing hormone (GnRH) induces the LH surge, while prostaglandin F2α (PGF2α) triggers luteolysis.
- A combination of GnRH and PGF2α analogs may enhance fertility outcomes in cattle.
- Timed artificial insemination (TAI) protocols are crucial for efficient cattle breeding.
Purpose of the Study:
- To evaluate a novel fixed-dose combination of Lecirelin and Cloprostenol (GPG) in TAI protocols for Nelore cattle.
- To assess the effects of GPG on ovulation timing, synchrony, and fertility (pregnancy per artificial insemination - P/AI).
- To investigate the mechanistic basis for GPG's effects on ovulatory follicle development.
Main Methods:
- Eight studies involving Nelore cattle subjected to TAI protocols were conducted.
- The GPG combination was compared against GnRH or PGF2α treatments.
- Ovulation timing, intrafollicular hormone concentrations (estradiol - E2), and gene expression (PTGS2) were analyzed.
- Fertility was evaluated by measuring pregnancy per artificial insemination (P/AI).
Main Results:
- GPG and GnRH induced earlier ovulation than PGF2α.
- GPG significantly reduced the dispersion of ovulation timing compared to GnRH alone.
- GPG treatment led to lower intrafollicular E2 concentrations and increased PTGS2 gene expression in the ovulatory follicle.
- Fertility outcomes (P/AI) showed variable results, with a tendency for improvement in some postpartum cows but no significant overall difference in large field studies.
Conclusions:
- The GPG formulation enhances ovulatory synchrony by upregulating PTGS2 expression and decreasing intrafollicular E2 concentrations.
- The improved ovulatory synchrony provides a mechanistic basis for the observed reduction in ovulation time dispersion.
- While GPG consistently improves ovulation timing, its effects on pregnancy per artificial insemination (P/AI) require further investigation.
