Impacts of GnRH, PMSG and HCG Treatments on Follicular Diameter, Conception and Lambing Rates of Egyptian Ewe Lambs Using Intravaginal Sponges

Abstract

The influence of gonadotropin releasing hormone (GnRH), Pregnant Mare Serum Gonadotropin (PMSG) and human Chronic Gonadotropin (hCG) on some reproductive responses of Egyptian ewe lambs was evaluated. Twenty five animals (aged 8 – 12 months and weighed 27 33 Kg) were divided into 5 groups ( 5 ewe lambs each). Group (1) served as a control, Group (2), received vaginal sponges impregnated with MAP (60 mg medroxy progesterone acetate) for 14 days, during this period, animals fed 3 kg Berseem, (Trifolium alexandrinum) plus 500 gm concentrate / head/ day. Group (3), received vaginal sponges impregnated with (60 mg, MAP) for 14 days, on the day of sponge removal; each animal injected by PMSG (250 IU, I/M). Group (4) animals received 1.25 ml Receptal (0.5 μg, GnRH) I/M, on day 0, seven days later, ewe lambs injected with 0.5 ml Estromate (125 μg. PGF2α) I/M, after 48 hours, animals treated with a second dose of GnRH. Group (5) received two injections of (0.5 ml Estromate) at days 0 and 7, respectively, after 72 hours from the second dose of PGF2α ewe lambs were injected 0.2 ml hCG. Heat detection was performed and transrectal ultrasound scanning also performed to confirm estrus, pregnancy and follicular diameter. The results revealed that, administration of PMSG (group 3) reduced the interval to estrus (the onset of heat /hours) significantly (P< 0.01) compared with control and other groups. Regarding conception and lambing rates, groups 2, 3, & 4 had affected significantly (P˂ 0.01) compared to groups 1 & 5. Follicular diameter (mm) tended to increase significantly in treated groups than the control one. Results suggest that, tested hormones have effect on selected reproductive responses of Egyptian ewe lambs while administration of PMSG (Group 3) has the best response compared to other hormonal treatments.