Endocrine profiles and embryo quality in the PMSG-PGF2alpha treated cow

Area of Science:

• Reproductive endocrinology in dairy cattle.
• Embryology and assisted reproductive technologies.

Background:

• Hormonal profiles, specifically progesterone and luteinizing hormone (LH), play a critical role in estrus synchronization and embryo development in dairy cows.
• Understanding these hormonal fluctuations is essential for improving reproductive efficiency in cattle breeding programs.

Purpose of the Study:

• To investigate the relationship between plasma progesterone and LH concentrations around estrus and embryo quality in PMSG-treated and control dairy cows.
• To compare the timing of estrus and the preovulatory LH surge in response to prostaglandin (PG) treatment between experimental and control groups.

Main Methods:

• Dairy cows and heifers (Holstein Friesian and Jersey breeds) were divided into PMSG-treated (experimental) and non-treated (control) groups.
• Plasma progesterone and LH concentrations were measured around estrus following prostaglandin (PG) injection.
• Estrus onset, interval to estrus, preovulatory LH surge timing and level, and embryo quality were assessed.

Main Results:

• PMSG-treated animals showed increased progesterone post-treatment, followed by a decrease after PG injection.
• Estrus occurred sooner in experimental animals (46.9 h) than controls (64.5 h); the LH surge also occurred earlier (41 h vs. 65 h).
• Experimental animals with optimal embryo quality (Group I) had lower pre-estrus progesterone and a higher LH surge level compared to those with unfertilized eggs (Group II).

Conclusions:

• Plasma progesterone and LH levels in PMSG-PGF2alpha treated dairy animals are significantly related to embryo or egg quality.
• Hormonal profiles, particularly LH surge characteristics and pre-estrus progesterone levels, can serve as indicators of successful fertilization and embryo development.