Fixed-time post-cervical artificial insemination in weaned sows following buserelin use combined with/without eCG

Area of Science:

• Reproductive biology and endocrinology in swine.

Background:

• Fixed-time post-cervical artificial insemination (FTAI) enhances efficiency and genetic selection in swine reproduction.
• Hormonal interventions are explored to synchronize ovulation for FTAI in weaned sows.

Purpose of the Study:

• To evaluate the efficacy of equine chorionic gonadotropin (eCG) with or without buserelin (GnRH agonist) for ovulation induction and synchronization in weaned sows undergoing FTAI.
• To assess the impact of these hormonal treatments on reproductive performance.

Main Methods:

• Three groups of weaned sows were studied: control (natural estrus insemination), eCG+GnRH (eCG followed by buserelin), and GnRH (buserelin only).
• Hormone administration timing and fixed-time artificial insemination (FTAI) protocols were standardized.
• Intervals to ovulation and reproductive parameters (farrowing rate, litter size) were recorded.

Main Results:

• Both eCG+GnRH and GnRH treatments significantly reduced the interval from weaning to ovulation compared to the control group.
• Sows treated with eCG+GnRH ovulated significantly earlier after buserelin administration than those treated with GnRH alone.
• The eCG+GnRH group exhibited lower farrowing rates and smaller litter sizes, attributed to insemination occurring outside the optimal window relative to ovulation.

Conclusions:

• While eCG and GnRH effectively synchronize ovulation in weaned sows for FTAI, the combination protocol (eCG+GnRH) requires precise insemination timing.
• Insemination for the eCG+GnRH group should ideally occur between 116-122 hours post-weaning to optimize reproductive outcomes.
• The GnRH-alone treatment shows potential for synchronizing ovulation without compromising reproductive performance, provided estrus is exhibited at insemination.