Question

Annual expected rate of genetic improvement through progeny testing is

• A. 0.5 %
• B. 5 %
• C. 5 %
• D. 5 %

Hint:

The long generation interval of progeny testing is its primary limitation, which is why modern dairy programs combine it with genomic selection to accelerate genetic progress.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Progeny testing is a selection method where the genetic value of an individual is estimated based on the performance of its offspring.
It is widely used in dairy cattle breeding for sex-limited traits like milk yield, which cannot be measured directly in males.

Step 2: Detailed Explanation:
The annual rate of genetic progress (\(\Delta G\)) in a selection program is determined by the selection intensity, the accuracy of selection, the genetic standard deviation, and the generation interval.
While progeny testing offers high selection accuracy because it uses records from many daughters, it also has a long generation interval because bulls cannot be evaluated until their daughters mature and complete a lactation.
This long generation interval limits the annual rate of genetic gain.
Under standard, well-managed progeny testing schemes in dairy cattle, the expected annual genetic improvement for milk yield is typically between \(0\%\) and \(5\%\) of the herd mean.
An annual gain of \(5\%\) represents an effective balance of selection intensity and accuracy within the constraints of the generation interval.
Gains of \(5\%\) or \(5\%\) are rarely achieved in practice using traditional progeny testing alone due to biological limits on reproductive rates and generation intervals in cattle.
Modern genomic selection is increasingly used to surpass these traditional limits by reducing the generation interval.

Step 3: Final Answer:
Thus, the annual expected rate of genetic improvement through progeny testing is approximately 5 %.