The effect of artificial insemination (AI), embryo transfer (ET) to bull dams (BD), and sexed semen (SS) to cow dams (CD) with and without controlling inbreeding were studied using stochastic simulation. Three levels of embryo transfer (no ET, ET on all BD, and ET on 20% of BD), five levels of sexed semen (no SS: control, SS-X on all CD, SS-X on 20% CD, SS-Y on all CD, and SS-Y on 20% CD), three levels of artificial insemination (no AI, AI on 50% cows, and AI on 90% cows), two levels of mating system (random and minimum consistory) were combined together to make 66 scenarios in which the combination of no ET, no SS, and no AI are assigned as a control. The simulated population consisted of 40 herds with 50 cows each was monitored for 30 years. The results showed that the use of AI, ET, and SS techniques increased the annual change of total merit index (TMI), inbreeding, and selection accuracy. Compared to control, the rate of annual change in TMI and inbreeding were increased as 41.95, 36.91 and 83.91%; and 192, 57 and 207%, for using of AI, ET and combination of SS + AI + ET, respectively. The minimum consistory mating decreased inbreeding, but not affected other parameters. The results suggested that using of ET on 20% BD, SS-Y for all CD, and 90% AI alone or in combination with each other along with minimum consistory mating might resulted in high genetic progress and low inbreeding rate. These technologies and inbreeding control strategies may increase the ratio of annual change of TMI to inbreeding. Manuscript profile

This study was conducted to evaluate the effect of dietary energy (ME) and protein (CP) on growth curve parameters and absolute growth rates in the different ages of the Khazak chicks. A total of 360 one-day-old Khazak chicks were obtained from a local hatchery and in a 3 × 3 factorial experiment with completely randomized design, chicks were randomly allocated to experimental diets including 2600, 2800, and 3000 kcal of ME/kg, and each containing 17, 19, and 21% CP from 7 to 98 days of age. Four growth model (Gompertz, Logistic, Lopez, and Richards) were fitted on weekly body weight data and the best model were selected by the goodness of fit criteria. Growth curve parameters were predicted for all chicks using the best model and other parameters including age (Ti) and weight (Wi) at the inflection point and absolute growth rate (AGR) in different ages were calculated from growth curve parameters. Based on goodness of fit criteria, the Richards model had the lowest Akaike’s Information Criteria (AIC), root mean square error (RMSE), and highest adjusted determination coefficient (R2Agj) than other models and was selected as the best model. The effect of ME was significant on the mature index (k), Wi, Ti, and all AGR parameters (P<0.05) while CP levels were significant on final weight (Wf), Wi, and AGR parameters (P<0.05). The chicks fed with a diet containing 2600 kcal of ME/kg and 17% CP had the higher k parameter, and lower Wi, Ti, and AGR than those fed with other diets (P<0.05). Considering that the level of 2800 kcal of ME/kg and 19% CP had no significant difference with the level of 3000 kcal of ME/kg and 21% CP, therefore diet with 2800 kcal of ME/kg and 19% CP was suggested as optimum levels for change the growth curve parameter and having best performance for Khazak chickens during 7 to 98 days of old. Manuscript profile