The effect of estrus synchronization with PMSG and FSH on some reproductive hormone in akkaraman ewes

The aim of the present study was to determine the effect of estrus synchronization with pregnant mare serum gonadotropin (PMSG) and follicle stimulating hormone (FSH) on plazma progesterone (P4), estrogen (E2) and luteinizing hormone (LH) at breeding and out of breeding seasons in Akkaraman ewes. In the present study, total 20 Akkaraman ewes, which had similar age and body weight, were used as experimental animal at breeding (September-November, n = 10) and out of breeding (April-June, n = 10) seasons. Forty-eight hours prior to estrus synchronization application of all ewes, intramuscular injection of 1 cc PGF2α was performed to lutalyse the corpus luteum (CL) on the ovary in both seasons. The vaginal CIDR device containing 0.30 g natural progesterone was then inserted into all ewes. CIDRs were withdrawn following 12 days and ewes were allocated randomly into two treatment groups in both seasons. Ewes in the first group were injected 600 IU PMSG and ewes in the second group were injected twice 300 µl (20 mg/ml) FSH at 12 hours intervals. In both seasons, blood was taken from jugular vena on intravaginal CIDR application (day 0), withdrawn CIDR (day 12), days 2 (day 14) and 5 (day 17) after FSH or PMSG injections from all ewes. Plasma P4, E2 and LH concentration were determined using commercial ELISA kits. In breeding season, PMSG applied sheep had higher (p<0.05) plasma P4 concentration than those of FSH applied on days 2 and 5 after hormones administration, but there were no significant differences between treatment groups in terms of plasma P4 concentration on trial days in out of breeding season. Similarly, although administration of PMSG increased (p<0.05) the concentration of plasma E2 compare to FSH administration on day 2 after hormones administration, there were no significant differences between treatment groups in terms of plasma E2 concentration in out of breeding season. There were no significant differences between treatment groups in terms of plasma LH concentration in both seasons, but administration of PMSG tended to increase (p=0.095) plasma LH concentration compare to FSH administration on day 2 after hormones administration in breeding season. In conclusion, PMSG application for estrus synchronization of Akkaraman ewes had more effect on plasma hormone concentration in breeding season compare to out of breeding season. Keywords: Estrus synchronization, Season, PMSG, FSH, Plazma hormone, Akkaraman