Superovulation and embryo transfer in Bos indicus cattle

Area of Science:

• Reproductive biology
• Veterinary science
• Animal reproduction

Background:

• Bos indicus cattle exhibit distinct reproductive physiology compared to Bos taurus breeds.
• Smaller follicle size and heightened gonadotropin sensitivity in Bos indicus impact estrus synchronization and embryo transfer programs.

Purpose of the Study:

• To evaluate follicular dynamics and superovulatory responses in Bos indicus donors.
• To implement fixed-time artificial insemination (AI) protocols in superstimulated Bos indicus cattle.

Main Methods:

• Utilized estradiol and progesterone/progestogen releasing devices for follicular wave control.
• Administered lower doses of Follicle-Stimulating Hormone (FSH) for superstimulation.
• Adjusted progesterone/progestogen device removal timing and gonadotropin-releasing hormone (GnRH) or pregnant mare serum gonadotropin (PMSG/pLH) administration for ovulation synchronization.

Main Results:

• Estrus control protocols were as effective in Bos indicus as in Bos taurus breeds.
• Synchronized ovulation was achieved by delaying device removal and administering GnRH/pLH post-FSH treatment.
• Fixed-time AI was successfully applied without estrus detection, maintaining positive results.

Conclusions:

• Fixed-time AI protocols are viable for Bos indicus cattle, adapting treatments for their unique physiology.
• Optimized hormonal protocols allow for efficient superstimulation and AI, improving reproductive efficiency in Bos indicus donors.