COMPUTING THE VARIANCE OF RESPONSE TO SIM ULATED SELECTION WITH DAM-DAUGHTERS PAIRS WHEN DAMS ARE RELATED

Selection with dam-daughters pairs is investigated using the Monte-car lo simulation. Approximation formulas were tested for expectation and variance of the selection differential and of the response to selectio n. With the exception of the variance of response to selection. result s of the MC-simulation were in good accordance with results of the app roximations. Simulation results are used for planning a comparison of two selection methods by using dam-daughters pairs. To compare statist ically index selection with phenotypic selection, for instance in the case h2 = 0.4, it is necessary to raise 160 dam-daughter pairs over 12 generations. Further, h2 estimation with dam-daughter regression was simulated for an underlying hierarchical full- and halfsib structure. Standard errors for the h2 estimations yielded an optimal proportion s elected dams of around 50 per cent. MC-simulation should be the method of choice for planning of selection experiments with parents-offsprin gs pairs over more than one generation.