Banca de QUALIFICAÇÃO: CÍNTIA BATISTA HURTADO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : CÍNTIA BATISTA HURTADO
DATE: 18/06/2025
TIME: 08:00
LOCAL: Embrapa Rondônia
TITLE:

Effect of Promov on the ovulation in beef cows

KEY WORDS:

GnRH; oocytes, Ovulation, PGF2α.

PAGES: 24
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Reprodução Animal
SUMMARY:

Two experiments were conducted to evaluate a novel hormonal combination for inducing ovulation in beef cows. In Experiment 1, Nelore cows (n = 25) were synchronized for ovulation using a timed artificial insemination (TAI) protocol based on estradiol (E2), progesterone (P4), prostaglandin F2α (PGF), and estradiol cypionate (EC). Six days after the initial TAI-induced ovulation, 500 μg of sodium cloprostenol (SC, a PGF2αanalogue) was administered to all cows. Thirty-four hours after this SC injection, the cows were subjected to a cross-over design, receiving either 25 μg of Lecirelin (GnRH) or 25 μg of Lecirelin + 500 μg of SC (Promov). Ultrasound was performed every 6 hours to detect ovulation. There were no significant differences (P > 0.05) between the groups in the time to ovulation or ovulation rate. In Experiment 2, Nelore cows (n = 19) were randomly assigned to receive either 25 μg of Lecirelin (GnRH group, n = 9) or 25 μg of Lecirelin + 500 μg of SC (Promov group, n = 10), following the same hormonal protocol as in Experiment 1 up to the treatment administration. Twenty hours after treatment, follicular aspiration was performed in all cows for analysis of intrafollicular (IF) concentrations of E2, P4, and PGFM, and gene expression analysis of steroidogenesis and ovulation-related genes in granulosa cells. Cows treated with Promov showed a significant increase (P = 0.05) in PTGS gene expression. The relative mRNA abundance of CYP19A1, HSD3B1, PGR, and STAR did not significantly differ (P > 0.05) between the groups. Cows treated with GnRH had significantly higher (P = 0.04) IF E2 concentration than cows treated with Promov In conclusion, while Promov did not alter the timing or rate of ovulation, it significantly affected intrafollicular gene expression (PTGS) and steroid concentrations (E2), suggesting it may alter the ovulation process and potentially impact fertility in cows subjected to TAI protocols. Field studies with a larger number of animals are needed to fully investigate the efficacy and implications of Promov in TAI procedures.

COMMITTEE MEMBERS:
Presidente - ***.305.370-** - LUIZ FRANCISCO MACHADO PFEIFER - EMBRAPA
Interno - ***.616.542-** - MOYSÉS DOS SANTOS MIRANDA - UFPA
Externa à Instituição - EVELYN RABELO ANDRADE OLIVEIRA - UNIR