Question

Gain in accuracy through multiple measurements is high when repeatability is

• A. low
• B. medium
• C. high
• D. very high

Hint:

For traits with low repeatability (such as service period or litter size), breeders should take multiple measurements to make accurate culling and selection decisions.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Repeatability (\(r\)) measures the strength of the relationship between repeated records of a trait in the same individual.
It sets the upper limit for heritability and represents the proportion of total phenotypic variance due to permanent genetic and environmental differences.

Step 2: Detailed Explanation:
The accuracy of estimating an animal's producing ability from \(n\) repeated records is given by the formula: \[ \text{Accuracy} = \sqrt{\frac{n \cdot r}{1 + (n - 1)r}} \]
Let us analyze the effect of repeatability (\(r\)) on this gain in accuracy:
High Repeatability (\(r \rightarrow 1\)): If a trait has high repeatability, a single measurement is already a highly reliable indicator of the animal's true genetic potential.
Taking additional measurements does not significantly improve accuracy, as the gain from multiple records is minimal.
Low Repeatability (\(r \rightarrow 0\)): If repeatability is low, a single measurement is heavily influenced by temporary environmental noise and is a poor indicator of true potential.
In this scenario, taking multiple measurements and averaging them helps cancel out temporary environmental variations.
This averaging significantly increases the accuracy of the estimation compared to taking a single record.
Therefore, the relative gain in accuracy from multiple measurements is highest when repeatability is low.

Step 3: Final Answer:
Gain in accuracy through multiple measurements is high when repeatability is low.