Superovulation and oocyte recovery in the ewe

Area of Science:

• Reproductive Biology
• Veterinary Science
• Endocrinology

Background:

• Superovulation protocols are crucial for enhancing reproductive efficiency in livestock.
• Horse anterior pituitary extract (HAP) and human chorionic gonadotrophin (hCG) are commonly used gonadotropins in these protocols.
• Optimizing superovulation treatments requires comparing different forms and combinations of these agents.

Purpose of the Study:

• To compare the efficacy of crude HAP versus soluble HAP, with or without hCG, for superovulating adult ewes.
• To evaluate the effects of these treatments on ovulation rate and oocyte recovery.

Main Methods:

• Thirty-eight adult ewes received a 12-day progestagen treatment.
• Ewes were subsequently treated with either crude HAP (135 mg) or soluble HAP (30 mg), with or without 1000 IU hCG.
• Ovulation rates and oocyte recovery were assessed post-treatment.

Main Results:

• Crude HAP yielded significantly higher ovulation rates (14.0) and ovarian response (15.3) compared to soluble HAP (6.3 and 9.4, respectively).
• Soluble HAP combined with hCG significantly increased ovulation rate (14.5) versus soluble HAP alone (5.3).
• Oocyte recovery was significantly higher with crude HAP (P < 0.05) than with soluble HAP.

Conclusions:

• Crude HAP is more effective than soluble HAP for inducing superovulation and improving oocyte yield in ewes.
• While soluble HAP with hCG shows some benefit, crude HAP demonstrates superior performance in this superovulation model.
• These findings suggest that the formulation of HAP significantly impacts its efficacy in reproductive treatments.