The objective ofthe present study was to compare the effect of different dosages of equine chorionicgonadotrophin (eCG) on the follicular dynamics and hormonal concentrations inAlpine goats. During the breeding season, the goats were submitted to estrousand ovulation synchronization with a device containing progesterone for 14 days.Female goats (n=24) were divided at random into four groups of 6 animals each.On the day of dispositive removal, the animals received 0 (Control), 200, 300and 400 UI of eCG. Follicular development was observed by ultrasonography oneday prior to administration of eCG until next ovulation. The plasma estradiol(E2) and progesterone (P4) concentrations were daily determinedusing RIA. All treated animals showed estrous. Estrous cycle with three andfour waves of follicular growth were observed. Size of the largest folliclewas smaller in control group animals of the third wave (5.5 ± 0.50 mm)when compared to those treated with 300 UI of eCG (7.17 ± 0.35 mm). Gonadotrophinincreased the number of small and medium follicles considering the control groupbecause the average number of corpora lutea were higher in 400 UI (4.27 ±0.23) females than those treated with 200 UI (1.95 ± 0.19). Plasma concentrationsof progesterone and stradiol showed differences among experimental groups. Combinationsamong progesterones and eCG is an adequate alternative for estrus synchronizationand support the development of new protocols for reproduction techniques assuperovulation and embryo transfer in goats.
