Question

In which stage of estrous cycle, a cow ovulates?

• A. Proestrous
• B. Estrous
• C. Metestrous
• D. Anestrous

Hint:

Remember this unique rule of cattle reproduction: "Cows are post-estrus ovulators."
They are the only major farm species that ovulate during metestrus rather than during active estrus.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The estrous cycle of farm animals consists of four main phases: proestrus, estrus, metestrus, and diestrus.
The timing of ovulation relative to these phases varies among species.

Step 2: Detailed Explanation:
Most farm animals (such as ewes, sows, and mares) ovulate during the latter part of the estrus (heat) phase.
However, the cow (cattle) is a major biological exception to this rule.
A cow does not ovulate while she is in active estrus (standing heat).
Instead, she ovulates approximately 10 to 15 hours after the end of estrus, which corresponds to the metestrus phase of the cycle.
Because ovulation occurs after she has gone out of heat, timing artificial insemination (AI) is critical.
AI is typically performed during late estrus (using the "AM-PM rule") so that viable sperm are present in the oviduct when the egg is released during metestrus.
If breeding is delayed until metestrus, conception rates are significantly lower.

Step 3: Final Answer:
A cow ovulates during the Metestrous stage of the estrous cycle.