A simulation study of genetic trend of growth traits and inbreeding in Zandi sheep breed

Modeling of breeding programs is useful to predict and compare the results before a strategy is implemented.
In order to compare of the genetic trend of growth traits and inbreeding in Zandi sheep with real condition, a simulation program was designed.
To design the simulating program, the R software of 2.13.0 version was used. Management parameters and average of traits in rural sheep production system for Zandi breed were used as input of the model. Economic values estimated for Zandi breed were used in selection index equations.
The results of a 15-year selection by the simulation method indicated that in the Zandi rural sheep production system, genetic improvement was positive for the traits under study. The accumulative genetic gain after 15 years for BW0, BW3, BW6 and BW9 were estimated to be 0.504, 3.008, 4.433 and 5.509 Kg respectively. The genetic trend of BW0, BW3, BW6 and BW9 were estimated to be 34.08 ±0.0007, 218.12±0.0057, 326.03 ±0.0086 and 395.20 ±0.0097 g per year respectively. The inbreeding coefficient average after 15 years was 1.411% and the aggregate genotype after 15 years of selection based on multi-traits index was 249883.7 Rls.
The genetic simulation results showed that with genetic evaluation by the convenient methods and selection intensity, it can be expected that the performance average due to genetic improvement in Iranian breeds is more changed compared with the current report is published.