Flushing vs. Hormonal treatment, which better improve the reproductive performance of Ossimi ewes?

Abstract
The purpose of the current investigation was to evaluate the effect of flushing and hormonal methods on reproductive performance in local Ossimi sheep. Thirty Ossimi ewes of 39.56 ± 0.72 kg average live body weight were used. Animals randomly divided into three groups. The first group (G1) (Flushing without hormonal treatment), the second group (G2) (flushing with injection of GnRH). While, ewes of the third group (G3) flushing and one injection of PGF2 + GnRH. The basal flushing applied by feeding a gradual increased concentrate pelleted mixture, 14% crude protein, started by 500 g/h/day up to 1 kg/h/d during two weeks started prior breeding until the breeding season beside added amount of rice straw. The experiment designed according to the complete randomized design (CRD). There was a significant effect (P≤0.05 or P≤0.01) due to the treatments on litter size at birth (LZB), fecundity rate (FR), net reproductive rate (NRR), birth weight (BW0), body weight at 10 wks (BW10), total daily gain from birth to 70 d. On the other hand, no significant differences were found due to treatments on laming rate (LR), litter size at weaning (LZW), overall reproductive rate (ORR), livability, body weight at 8 wks (BW8), and kilograms of lambs born (KLBEL) and weaned (KLWEL). As conclusion, enhancing ration during breeding period is enough to improve the reproductive performance of ewes. The reason of reduced fertility with hormonal treatments may be due to increasing GnRH level against exert inhibitory effects or blocking of GnRH receptors by chemical antagonists of GnRH.