The effect of higher nutrition around ovulation time and gonadotropin hormones on reproductive performance of Naeini ewes was studied in 3 sperated expriments. The experiment 1 was conducted to compare the effect of high energy or high energy-protein diets in long-term (16 days) or short-term (6 days) supplementation period on ovarian performance and serum metabolites and hormones of ewes. Results of this study revealed that change in dietary energy levels for a short-term or long-term period just before ovulation could improve the blood metabolites and reproductive performance of ewes. The experiment 2 was conducted to compare the effect of transient high-energy diet in a short-term period with or without eCG injection on follicles development, twining rate, serum metabolites and hormones in ewes. Results showed that ovulation rate, twin births, fecundity and prolificacy was greater in ewes fed high energy diets. Feeding high energy diets increased serum glucose, cholesterol and insulin, but decreased serum urea nitrogen near the time of ovulation. After the start of experiment, ewes fed high energy diets had lower serum estradiol. However, one day after sponge removing, serum estradiol in high energy groups increased. It was concluded that short-term (6-day) changes in dietary energy level with or without eCG injection increased twin births and had beneficial effect on the blood metabolites and hormones concentrations in Naeini ewes. The experiment 3 was designed to determine the effect of short-term nutritional supplementation with or without hCG injection on reproductive traits and serum concentrations of selected metabolites and metabolic and reproductive hormones in eCG superovulated Naeini ewes. The results showed that short-term (6- day) changes in dietary energy level attendant with eCG and hCG injection had beneficial effects on the blood metabolites and the hormones concentration and also, on the twining rate and lambing rate in Naeini ewes.