Evaluation of the Superovulatory Effect of Pregnant Mare’s Serum Gonadotropin (pmsg) and Follicle Stimulating Hormone (fsh) in the Non-breeding Season of River Buffaloes of the Miankaleh Peninsula, Northern Iran

Ten primiparous river buffaloes of the Miankaleh peninsula, northern Iran in the nonbreeding season from the native herds were selected. The buffaloes were divided into two groups (n=5) and were injected intramuscularly with gonadotropin releasing hormone (GnRH) and a controlled internal drug-release device (CIDR) inserted on the fi rst day. Ten days later, administration of follicle stimulating hormone (FSH) in the fi rst group and pregnant mare’s serum gonadotropin (PMSG) in the second group based on determined protocols were done. Concurrent to prostaglandin administration, CIDRs were removed and followed by estrus detection. Artifi cial insemination was done twice a day in both groups. Ovarian activity was assayed by ultrasonography on the fi rst and fi fth day after the start of the superovulation program. Buffaloes in which no oocyte/embryo was recovered by uterine fl ushing were considered non responsive to the embryo collection and were not injected with PGF2α. Fifty days after insemination, pregnancy detection was performed by rectal ultrasonography. The mean (±standard deviation, SD) of follicles diameter on right ovaries in the fi rst day in the FSH group (9.5±1.8 mm) was less than in the PMSG group (11.1±1.1 mm, P=0.006). The mean (±SD) number of follicles on both ovaries in the fi fth day in the FSH group (7.4±0.8) was signifi cantly greater than that in the PMSG group (5.0±2.0; P=0.032). However, no oocyte/embryo was recovered in either group. Pregnancy detection 50 days after insemination showed that one cow of the FSH group and four cows of the PMSG group were pregnant. In conclusion, the PMSG and the FSH regimes induced follicular growth, but embryo recovery was poor during the non-breeding season in river buffaloes of the Miankaleh peninsula.