Serum oestradiol and progesterone profiles and their relationship with superovulatory responses in Tellicherry goats treated with eCG and FSH

摘要

Twenty-seven healthy, parous and cyclic Tellicherry goats were divided into three equal groups based on administration of follicle stimulating hormone of porcine origin (FSH-P), follicle stimulating hormone of ovine origin (FSH-O) or equine chorionic gonadotrophin (eCG) as a superovulatory treatment. The oestrous cycle in all the goats was controlled by inserting 3 mg norgestomet ear implants, combined with a 0.5 ml of injection containing 1.25 mg oestradiol valerate and 0.75 mg norgestomet (Day 1). The superovulation treatment was initiated on Day 10 of the experiment with 190 mg NIH-FSH-P-1 in eight decreasing doses of 32:32, 24:24, 18:18, 16:16 mg subcutaneously twice daily at 12 h interval for 4 days in FSH-P group, 180 mg of NIH-FSH-S-1 in eight equal doses of 22.5 mg subcutaneously twice daily at 12 h interval for 4 days in FSH-O group and 1000 IU eCG intramuscularly as a single dose in eCG group. The ear implants were removed on Day 12 and 10 mg of PGF(2alpha) was administered 12 h before implant removal in all three groups. All goats were bred to fertile bucks 36, 48 and 60 h after implant removal. Embryo collection was performed surgically from the oviducts; 3 days after the first service. The daily serum oestradiol 17beta and progesterone concentrations were determined using RIA. The number of ovulation, total embryo recovery and number of transferable embryos were significantly higher in FSH-O group than FSH-P and eCG groups. The oestradiol level was elevated immediately after initiation of gonadotrophin treatment and a peak level was observed 2 days after implant removal, decline thereafter. The oestradiol concentrations on the day of oestrus and embryo collection were significantly higher in eCG and FSH-P group than FSH-O group. The serum oestradiol concentrations on the day of implant insertion, onset of gonadotrophin treatment and embryo collection were negatively correlated with the number of ovulations and total embryo recovery and number of transferable embryos. The oestradiol producing capacity of anovulatory follicles had more negative impact on embryo recovery rate and embryo quality than their number. Oestradiol concentrations on day of oestrus and progesterone concentrations on the day of embryo collection showed a positive correlation with the number of ovulations, embryo recovery and transferable embryos. It is concluded that the FSH-O preparations can be preferred as a gonodotrophin of choice for superovulation of Tellicherry goats. Serum oestradiol and progesterone concentrations during superovulation program have a greater correlation with superovulatory responses in Tellicherry goats.