Determining the optimal selection index without using economic coefficients in native fowls of Yazd province

The aim of this study was to design optimal selection index without the use of economic coefficients based on the expected genetic gains in economic traits. Random simulation with 5 replications was used to evaluate the results of the designed indices. Simulated traits include body weight at birth (BW1), eight weeks (BW8), twelve weeks (BW12), maturation (BWM), age at first laying (AFE), weight of first egg (EWM), the mean egg weight from 28 to 32 weeks (EW) and the egg number (EN). In three indices, BW12, EN and EW traits were in the selection target and all simulated traits were in the selection criterion. Indices with the aim of genetic gain for 5 g in EW, 20 in EN and the difference between the three indices of the first to third selection were related to the change in the expected values of 100, 200 and 300 gr in BW12. The results showed that all three selection indicators are able to create a uniform and desirable genetic gain in traits. However, the second index is able to achieve acceptable results in a smaller number of generations (304 gr, 25.3 and 6.4 gr genetic gain for BW12, EN and EW, respectively). The inbreeding after 5 generations of the implementation of the first to third indices was not desirable (approximately 0.02) and the difference in inbreeding between the indices was not significant (P> 0.4). It is suggested that the second index for 5 generations be used for the Yazd province native fowls breeding.