The effect of prostaglandin (PGF2a) vs CIDR and eCG (equine chorionic gonadotrophin) on follicular dynamic of wave 1 and its relation with P4 and E2 plasma concentrations were investigated in cyclic ewes. Fourteen Bergamascia ewes were used, Group 1 (G1) synchronized by two i.m. injections of PGF2alpha and Group 2 (G2) treated for 14 d with CIDR and 500 IU of eCG at dispositive withdrawal on day 14. Ovarian follicular dynamics were ultrasonically monitored. All the ovarian follicles > 2 mm were measured, and their relative locations were recorded on an ovarian map in order to follow the sequential development of each individual follicle. Blood samples for P4 and E2 determination were collected daily from 1 d before the second injection of PGF2alpha (G1) and administration of eCG (G2) until day 10 after ovulation of the cycle. There were significant differences in P4 and E2 plasma concentrations between treatments. The CIDR + eCG (500 IU) treatment enhanced the recruitment of smaller follicles and enhanced the maximum diameter and growth rate of large follicles during wave 1.
follicular dynamics; oestradiol (E2); ovine; progesterone (P4); ultrasonography
