Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : In cows, insemination should be preferably done a few hours before the ovulation.
Reason (R) : Sperm capacitation and acrosomal reaction in the genital tract of cow may take about six hours.
In light of the above statements, choose the correct answer from the options given below

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

- AM-PM Rule: Cows observed in standing heat in the morning (AM) should be inseminated in the afternoon/evening (PM).
- Cows observed in heat in the afternoon (PM) should be inseminated the following morning (AM).
This ensures optimal timing relative to ovulation.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
To achieve high conception rates in artificial insemination (AI), the timing of insemination must be precisely synchronized with the cow's estrus and ovulation cycle, taking into account the physiological lifespan of both gametes.

Step 2: Detailed Explanation:
Let us analyze both statements and their relationship:
- Assertion (A):
Ovulation in cows is spontaneous and occurs approximately 10 to 15 hours after the end of standing estrus (heat).
The ovulated oocyte remains viable and capable of fertilization for only about 6 to 12 hours.
To ensure that viable sperm are present in the oviduct when the oocyte arrives, artificial insemination should ideally be performed several hours before ovulation occurs (typically during mid-to-late standing heat, following the "AM-PM" rule).
Therefore, Assertion (A) is correct.
- Reason (R):
Ejaculated or cryopreserved spermatozoa are not immediately capable of fertilizing an oocyte upon deposition.
They must spend approximately 6 to 8 hours within the female reproductive tract to undergo capacitation (removal of membrane cholesterol and glycoproteins) and the acrosome reaction (release of enzymes to penetrate the zona pellucida).
Because of this mandatory preparation time, inseminating cows a few hours before ovulation ensures the sperm are fully capacitated and ready to fertilize the egg immediately upon ovulation.
Therefore, Reason (R) is correct.
- Relationship between (A) and (R):
Since sperm require about six hours in the female tract to undergo capacitation (R), insemination must be performed several hours before ovulation (A) so that fertilizable sperm are present in the oviduct when the egg is released.
Thus, (R) is the correct explanation of (A).

Step 3: Final Answer:
The correct option is (A).