In reproductive biotechnology and animal breeding, “superovulation” refers to the induction of multiple ovulations in a single cycle. Which underlying follicular change primarily explains this outcome?

Introduction / Context:
Superovulation is widely used in assisted reproduction and animal breeding programs to obtain multiple oocytes from a single estrous cycle. Understanding the follicular physiology that drives this response is critical for optimizing hormone protocols and improving embryo yields.

Given Data / Assumptions:

• Follicles pass through waves of recruitment, selection, dominance, and atresia.
• Exogenous gonadotropins (for example, FSH) support additional follicles that would otherwise undergo atresia.
• Follicular size categories matter; medium to large antral follicles are closest to ovulatory competence.

Concept / Approach:
In a natural cycle, many antral follicles enter a wave but most undergo atresia, leaving one dominant follicle. Superovulatory treatments reduce atresia among a cohort of medium and large follicles, allowing several to progress to preovulatory status. Therefore, the key mechanism is decreased atresia in the follicles that are already near selection or dominance thresholds.

Step-by-Step Solution:

Verification / Alternative check:
Ultrasonographic monitoring during superovulation shows a larger cohort of growing, non-atrophying medium–large follicles progressing together toward ovulation compared with natural cycles.

Why Other Options Are Wrong:

• B: Increased atresia would reduce, not increase, ovulations.
• C: The size criterion is incorrect and still predicts fewer ovulations.
• D: Small follicles are less critical; rescuing very small follicles is inefficient within the short stimulation window.
• E: Protocols clearly alter atresia dynamics.

Common Pitfalls:
Confusing recruitment with selection; assuming superovulation creates new follicles rather than rescuing existing antral follicles from atresia.

Final Answer:
Decreased atresia in medium and large follicles (> 1.7 mm)