Effect of excluding age at sexual maturity from breeding goal and ratio of selected roosters on selection response of traits in native fowls

The aim of the current study was to investigate the effect of removing age at sexual maturity in native fowl breeding goal. Therefore, a deterministic simulation for single stage selection with discrete generations was used to estimate genetic and economical responses as well as inbreeding rate. The first aggregate genotype consisted of body weight at eight weeks of age, average of egg weight at 28, 30 and 32 weeks, egg number and age at sexual maturity. In this case, genetic gains for body weight at eight weeks of age, average of egg weight at 28, 30 and 32 weeks and egg number were 53.19, -0.207 and 13.02, respectively. The second program was the same as the first whereas only age at sexual maturity was excluded. This is followed by decreasing genetic gain for egg number. On the other hand, accuracy of selection also decreased. Decreasing accuracy of selection is related to increase breeding goal variance. Changing the number of selected sires in breeding program showed the selection proportion of two percentages in sires was led to optimal genetic gain for breeding goal’ traits. In this case, inbreeding coefficient is about one percent which is optimum for poultry breeding programs.