Question

Given below are two statements:
Statement (I): Repeatability can be used for the prediction of future performance.
Statement (II): Repeated observations on a cow have greater advantage to estimate the most probable producing ability when repeatability is small.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

The accuracy (\( g \)) of estimating an animal's producing ability from \( n \) records is:
\[ g = \sqrt{\frac{n \cdot r}{1 + (n-1)r}} \] When repeatability (\( r \)) is small, increasing the number of records (\( n \)) significantly improves the accuracy of the estimate.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Repeatability (\( r \)) is the correlation between multiple records of the same trait made on the same individual over its lifetime (such as milk yield across different lactations).
It expresses the proportion of the total variance that is due to permanent differences (both genetic and environmental) between individuals.

Step 2: Detailed Explanation:
Let us evaluate both statements:
Statement (I) is correct.
Repeatability is used to estimate an animal's Most Probable Producing Ability (MPPA).
By measuring an animal's performance in its first lactation or shearing, we can use the repeatability value to predict its future performance, which helps guide culling decisions.
Statement (II) is correct.
If a trait has low repeatability, a single record contains a high proportion of temporary environmental error and is a poor indicator of the animal's true producing ability.
Taking multiple repeated observations averages out this temporary environmental error, significantly improving the accuracy of the MPPA estimate.
If repeatability is already very high, a single record is a highly accurate indicator of true producing ability, and taking additional records provides little extra benefit.
Therefore, both statements are correct.

Step 3: Final Answer:
Both Statement (I) and Statement (II) are correct.