EFFECT OF OVARIAN SYNCHRONIZATION PROTOCOLS, USING GnRH AND PGF2, ON OVARIAN RESPONSE AND REPRODUCTIVE TRAITS OF RAHMANI EWES

SUMMARY
Thirty Rahmani ewes were used to study the effect of ovsynch protocol (GnRH+PGF2) on the reproductive performance of Rahmani ewes. They were equally divided into three treatment groups. All ewes in the treated groups were intramuscularly injected on Day (0) with 1 ml GnRH analogue, (Receptal®) followed by intramuscular injection of 0.7 ml PGF2α analogue (Estrumate) either by 5 days (G1), 6 days (G2) or 7 days (G3) . A second dose of GnRH analogue (1 ml) was given on day-7 (G1), day-8 (G2) or day-9 (G3), and artificial insemination was carried out 24 h later.
Results showed that 1 out of 10 ewes exhibited estrous activity in G1 vs. 3 out of 10 ewes in both G2 and G3. Ewes in G1 had the highest (P<0.05) lambing rate (60%), compared to G2 (50%) and G3 (40%). Litter size and fecundity were higher (P<0.05) in G1 (1.67 lambs/ewe and 100%), followed by G2 (1.40/lambs/ewe and 70%) and G3 (1.25/lambs/ewe and 50%). P4 concentration was high (P<0.05) in all treated groups as affected by the 1st GnRH injection. Thereafter, P4 decreased in all treated groups after PGF2 injection. Post-2nd GnRH injections, P4 levels showed a pronounced increase in all treated groups. At days 21to 24 post-mating, P4 levels showed the highest values in all treated groups.Based on the obtained results, using GnRH-PGF2α-GnRH (GnRH, 0 d; PGF2α 5 d laterandGnRH 48 h later) protocol during the breeding season (January) can be used for synchronization of ovulation to reduce service and lambing intervals of Rahmani ewes.