Ovulation, fertilization and pronucleus development in superovulated gilts

Area of Science:

• Veterinary Science
• Reproductive Biology
• Swine Reproduction

Background:

• Estrus synchronization is crucial for efficient swine artificial insemination programs.
• Optimizing ovulation and fertilization timing is key to maximizing reproductive success in gilts.

Purpose of the Study:

• To evaluate the efficacy of Zinc-Methallibur for estrus synchronization in gilts.
• To determine the optimal timing for insemination and embryo recovery after hormonal induction of ovulation.
• To assess early embryonic development following synchronized estrus and insemination.

Main Methods:

• Estrus was synchronized in 45 gilts using Zinc-Methallibur for 15 days.
• Hormonal treatment involved PMSG (Pregnant Mare Serum Gonadotropin) and hCG (human Chorionic Gonadotropin) injections.
• Gilts were inseminated at 24 and 36 hours post-estrus onset, with groups slaughtered at timed intervals (40-64 hours post-hCG) for oocyte/embryo recovery.

Main Results:

• Ovulation rate increased from 38% to 87% between 40 and 45 hours post-hCG.
• Fertilization rates progressively increased from 36% at 40 hours to a peak of 80% at 60 hours post-hCG.
• Early embryonic development, including pronuclei formation and first cleavages, was observed within 52-64 hours post-hCG.

Conclusions:

• Zinc-Methallibur effectively synchronizes estrus in gilts, facilitating predictable ovulation and fertilization.
• Insemination timing 24-36 hours after estrus onset, coupled with hCG administration, leads to high fertilization rates.
• The study provides a detailed timeline of early embryonic development in hormonally synchronized gilts, valuable for reproductive management.