Video Experimental Relacionado

Updated: Jan 18, 2026

In Vitro Culture Strategy for Oocytes from Early Antral Follicle in Cattle

In Vitro Culture Strategy for Oocytes from Early Antral Follicle in Cattle

Published on: July 8, 2020

Eficiencia reproductiva de vacas Bos indicus bajo diferentes protocolos de sincronización de la ovulación sin

Lucas Araujo Lemos¹, Laís Reis Carvalho¹, Matheus Pedroso Vicente¹

¹Faculty of Animal Science and Veterinary Medicine, UFLA, Lavras, MG, Brazil.

|January 15, 2026

Abstract:

The objective was to evaluate the fertility of Bos indicus cows submitted to an ovulation synchronization protocol without estrogen (E2). In experiment 1, injectable P4 (P4i) was administered 10 days (D-10) before the TAI protocol. On D0, cows received one intravaginal P4 device and estradiol benzoate (EB; Control) or buserelin acetate (GnRH/EC and 2GnRH). On D8, devices were removed, and all cows received eCG and PGF2α. Additionally, cows received estradiol cypionate (EC) on D8 (Control and GnRH/EC) or buserelin acetate on D10 (2GnRH). In Experiment 2, cows in the Control group underwent a protocol similar to Experiment 1. Cows in the GnRH/EC, 2GnRH/48h, and 2GnRH/54h groups were pre-synchronized with an intravaginal P4 device (D-7) and received gonadorelin and an intravaginal P4 device on D0. P4 devices were removed on D8, and all cows received eCG and PGF2α. Furthermore, the GnRH/EC group received EC, and cows in the 2GnRH/48h and 2GnRH/54h groups were administered GnRH 48 h (h) after removal of the P4 device. TAI was performed 48 (2GnRH/48h) or 54h (2GnRH/54h) after removal of the P4 device. In all experiments, the follicular diameter on D8 was greater in cows that received GnRH on D0 (P ≤ 0.01) as well as a greater ovulation rate on D0 (P ≤ 0.01). Furthermore, estrus expression was greater in cows receiving EC (P = 0.001; Exp. 2). P/AI was greater in the Control group (P = 0.001; Exp. 2). In conclusion, removal of estradiol in ovulation synchronization protocols resulted in lower fertility relative to E2-based controls.

Palabras clave:

GnRH Nelore Ovulación Prohibición

Más Videos Relacionados

A Modified Co-Culture System for Understanding Granulosa-Theca Cell Interactions in the Bovine Ovary

A Modified Co-Culture System for Understanding Granulosa-Theca Cell Interactions in the Bovine Ovary

Published on: September 19, 2025

Author Spotlight: Inducing Pseudopregnancy in Female Mice Without the Need for Vasectomized Males Prior to Non-Surgical Embryo Transfer or Artificial Insemination

Author Spotlight: Inducing Pseudopregnancy in Female Mice Without the Need for Vasectomized Males Prior to Non-Surgical Embryo Transfer or Artificial Insemination

Published on: July 7, 2023

Videos de Conceptos Relacionados

Ovarian Cycle

Ovarian Cycle

The menstrual cycle includes a critical component known as the ovarian cycle, which undergoes two main phases each month—the follicular phase and the luteal phase. The follicular phase is variable and averaging around 14 days. Ovulation, triggered by a surge in luteinizing hormone (LH), marks the transition between the two phases. The second phase, the luteal phase, is relatively consistent, lasting approximately 14 days, and is marked by the activity of the corpus luteum. While a cycle...