Comparison of hCG and GnRH for synchronization of the follicular wave in saanen goats during the breeding seasonDogan, Ibrahim (Avtor) Toker, Mehmed Berk (Avtor) Aktar, Ahmet (Avtor) Yilmaz, Mehmet Melih (Avtor) Huraydin, Oguzhan (Avtor) Udum, Duygu (Avtor) estrus synchronizationfolliclehCGGnRHgoatThis study aimed to compare the effects of a single dose of GnRH or hCG administered at the beginning of the short-term oestrus synchronization protocol on ≥4 mm diameter follicles in Saanen goats during the breeding season. The goats es-trus cycles were synchronized with intravaginal sponges containing 60 mg of medroxy-progesterone acetate for five days. Additionally, 1 ml of physiological saline solution (control-group; n=30), 0.004 mg of buserelin acetate (GnRH-group; n=31) or 150 IU of hCG (hCG-group; n=31) were injected intramuscularly to the goats during the sponges insertion. Transrectal ultrasonographic examination was performed immediately be-fore and 24 h after intravaginal sponge application into all goats and follicles with a diameter of ≥4 mm in the ovaries were counted. Blood samples were collected on the same days to determine serum progesterone (P4) and estradiol (E2) concentrations. At the first ultrasonographic examination, the percentages of ≥4 mm diameter follicles were 56.66% (17/30), 54.83% (17/31) and 70.96% (22/31) in the control, GnRH and hCG groups, respectively. The percentage of goats with reduced follicle diameters 24 h later was 29.41% (5/17), 52.94 (9/17) and 59.09% (13/22) in the same groups, respectively. The mean regression rates of follicle diameters between days 0 and 1 in each group were significantly different (P<0.05). Serum E2 concentrations were significantly differ-ent (P<0.05) between days 0 and 1 in hCG group. There were no differences in serum E2, P4 concentrations and mean regression rates in follicle diameters between days 0 and 1 for all groups. As a result, a significant relationship between the administration of hCG or GnRH and the reduction of large follicle diameters could not be established.20242025-03-28 13:56:49Članek v reviji168106UDK: 636.3:577.175.6ISSN pri članku: 1580-4003DOI: 10.26873/SVR-1787-2023COBISS_ID: 228780547sl