8.2 Estimating breeding values and selection response

The breeding value can be based on any uniformly related individuals to the animals or own record, see applet 7.2, remember the actual relationships a and a' should be properly defined. By pressing the Calculate button the accuracy is transferred to the delta G input window.

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In all green fields you should define values then press the Calculate button. The delta G can be run independently of the breeding value estimations, all values in the yellow fields shall be defined.
The selection response is calculated in the lower 3 rows of the applet according to the formula shown below. The delta G is calculated per year (år). If the generation interval is set to one year the results is also per generation. The parameters are
Selection intensity, i
Accuracy of selection, rAI
Generation interval, L
The additive standard deviation, sigmaA


Example:
The accuracy is automatically transferred from the breeding value estimation, but you can also convert an externally derived accuracy squared by means of r2 to r button. If you have the proportion selected (p) put your data in the (i) field and press the convert p to i button.
The calculation is based on the average of the contribution from the sires and dams. With the given initial parameters delta G is 0.04 units if you press the Calculate delta G button.
Questions:
In a population are selected 10 % males based on progeny test of 20 offspring and 50 % females based on own performance. SigmaA is set to 1.
Calculate delta G per generation when the heritability is 0.40.

If the males as well as the females were selected on own performance calculate delta G.
Compare the two results

Repeat the calculations with a heritability of 0.10


Back to theory, Back to theory (in Danish) or back to the other applets