Effect of Missing Sire Pedigree Informationon on Genetic Trend and Gain of Quantitative Trait using Computer Simulation

In order to study the effect of incomplete sire's pedigree on genetic trend (bBv,y) and gain (R) of quantitative trait, two population were simulated with the heritability 0.15 and 0.30. For each population, information resulted from ten years of selection were saved in different files. In generated data files, the sire numbers were eliminated from pedigree file with 0, 10, 20, …, 100 percentage by two randomly and sequentially methods. The data files were analyzed using animal model. In two populations and the sire numbers deletion method, genetic trend were significantly reduced with increasing the sire number deletion proportions. Reduction of estimated genetic trends in no sire numbers data file rather than complete pedigree's and simulated base population, were 86.18% and 89.1% in population 1 and 88.42% and 90.16% in population 2 respectively. Reduction of bBv,y and R in lower deletion proportions were higher than the later one in random deletion method while were uniformly in the sequential deletion method. Annually genetic gains were significantly decreased based on growing sire missing proportions. Then, it is necessary for breeders to increase accuracy of sire numbers recording in breeding flocks.