Designing of optimum selection index for Afshari sheep breeding under rural production system

This study was achieved to evaluation of some strategies and determination the best suitable selection index for Afshari sheep using simulated data. The relative importance of traits was determined based on the estimated economic values and consequently، the most benefit traits were applied to selection indexes construction. The interest indexes were different combination of traits including ewe body weight (EBW)، annual wools weight (AWW) and total weaning weight for each exposed ewe (TWWEE). The index 1 were included all three mentioned traits. The indexes 2، 3 and 4 were included (AWW، TWWEE)، (EBW، TWWEE) and (TWWEE)، respectively. The results indicated that the aggregate genotype، selection index and economic progress increased by increasing in the population size and decreasing in ram ratio، but made reduction in inbreeding average، in all indexes. In more cases، the aggregate genotype decreased by removing a trait in the index. The comparisons among indexes indicated that the most suitable selection index for this breed is index 1 which included EBW، AWW and TWWEE. This index had a maximum selection index average، aggregate genotype and economic progress.