Question

Ovulation during primary oocyte stage occurs in which of the following species?
A. Cow
B. Buffalo
C. Bitch
D. Mare
E. Goat
Choose the correct answer from the options given below:

• A. A and B only
• B. D only
• C. C only
• D. A and E only

Hint:

Oocyte Ovulation Stages:
Bitch (Canines) $\rightarrow$ PRIMARY OOCYTE (Meiosis completes in oviduct over 2-3 days).
Cow, Mare, Ewe, Sow, Woman $\rightarrow$ SECONDARY OOCYTE (Metaphase II).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Comparative female gametogenesis and meiotic maturation: canine and vulpine oocytes are unique among domestic mammals in ovulating as immature primary oocytes at the Dictyate germinal vesicle stage.
Key Formula or Approach:
\[ \text{Most Mammals (Cow, Mare, Ewe): Ovulate at Secondary Oocyte (Metaphase II)} \]
\[ \text{Bitch \& Vixen (Canids): Ovulate at Primary Oocyte (Dictyate Stage)} \]

Step 2: Detailed Explanation:
In comparative reproductive physiology and oogenesis:
1. Most Domestic Mammals (Cow, Buffalo, Mare, Ewe, Sow, Queen, Goat): The preovulatory LH surge triggers resumption of meiosis I, extruding the first polar body; ovulation occurs at the Secondary Oocyte stage arrested at Metaphase II.
2. Canines (Bitch) and Foxes (Canidae): Ovulate an immature Primary Oocyte with an intact germinal vesicle (arrested in diplotene/dictyate of meiosis I) surrounded by dense cumulus cells. Meiotic maturation (extrusion of 1st polar body to reach metaphase II) occurs in the oviduct over the subsequent $48 - 72\text{ hours}$ post-ovulation, explaining the physiological delay required for post-ovulatory fertilization in bitches.

Step 3: Final Answer:
Thus, ovulation during the primary oocyte stage occurs in C only (Bitch), matching option (C).