Neuroendocrine Control of Estrus and Ovulation

Gonadotropin-Releasing Hormone (GnRH) and Its Agonists in Bovine Reproduction II: Diverse Applications during Insemination, Post-Insemination, Pregnancy, and Postpartum Periods

“…The interval from parturition to the resumption of ovarian activity is essential in the reproductive cycle of dairy cows, marked by distinct physiological changes and significant commercial implications. Several factors contribute to the occurrence and persistence of anovulatory periods during the postpartum phase, including diminished LH release in late gestation, nutritional status during the peripartum period, mainly if there is a negative energy balance, and the influence of suckling stimulus in lactating cows nursing calves [ 14 ].…”

“…The presence of follicular wave patterns and follicles larger than 9 mm in diameter in the ovaries prompts the administration of GnRH. This induces an LH surge, leading to ovulation from the DF during the early postpartum period in dairy cattle [ 14 ]. The subsequent reduction in E 2 concentrations, ovulation triggered by GnRH treatment, and the rise in P 4 concentrations from CL development contribute to improved reproductive outcomes [ 62 ].…”

“…In the critical postpartum period (within 50 to 60 days postpartum) for dairy herds, hormonal treatments, including GnRH, are employed to synchronize reproductive functions and induce ovulation [ 14 ]. In beef herds, administering GnRH treatment during the postpartum period to induce ovulation of the first postpartum dominant follicle (DF) during the plateau/early declining phase of DF growth enhances ovarian functions.…”

Gonadotropin-Releasing Hormone (GnRH) and Its Agonists in Bovine Reproduction I: Structure, Biosynthesis, Physiological Effects, and Its Role in Estrous Synchronization

“…It was initially identified as a neuropeptide that regulates secretions from the anterior pituitary gland [1]. While GnRH serves various functions in mammals, research has mainly focused on its role as a gonadotropin-releasing factor, influencing reproductive processes by regulating the production and release of pituitary gonadotropins, thereby affecting steroidogenesis and gametogenesis [2,3]. This Animals 2024, 14, 1473 2 of 24 essential function has sustained ongoing interest in GnRH because of its significance as a critical regulator of reproductive functions across species.…”

“…Animals 2024, 14, x FOR PEER REVIEW 2 of 23 pituitary gonadotropins, thereby affecting steroidogenesis and gametogenesis [2,3]. This essential function has sustained ongoing interest in GnRH because of its significance as a critical regulator of reproductive functions across species.…”