Estrus synchonization of Saanen goats with intravaginal sponge and CIDR-G®

Two short synchronization protocols associated to the estradiol cipionate (EC) for estrus duration were compared. Twelve Saanen breed goats were used (eight multiparous (M) and four nuliparous (N)) in two treatments. T1 (n=4M and 2N) animals received an insertion of sponge intravaginal (ID) impregnated with 60mg of medroxyprogesterone acetate, and T2 (n=4M and 2N) animals received a CIDR-G((R)) At the device (d=0) insertion time, 1mg of CE was injected in animals from both treatments. On day 5, the ID was removed and the animals were observed for estrus detection every six hours. Ultrasonographic exams were performed daily during the device treatment and at every six hours after the estrus detection, up to 12 hours after the ovulation. A follicular regression occurred at the emergence of a new wave in the fifth day of the permanence of the device CIDR-G((R)) (day 0 = insertion device day). The estrus and pregnancy rates for goats were 516 and 115 for T1 and 616 and 216 for T2, respectively. Intervals from removal of the device to the onset of estrus and from removal of the device to the end of estrus, and estrus duration, were 74.0 +/- 39.1h and 34.7 +/- 15.1h (P < 0.05), 137.2 +/- 42.1h and 90.0 +/- 11.2h (P < 0.05), and 63.2 +/- 24.9h and 55.3 +/- 17.2h (P > 0.05), for T1 and T2, respectively. Intervals from the onset of estrus to ovulation, from the end of estrus to ovulation, and from removal of the device to ovulation, were: 50.6 +/- 22.6h and 47.3 +/- 15.3h (P > 0.05), -12.6 +/- 9.1h and -8.0 +/- 4.5h (P > 0.05), and 124.6 +/- 34.1 and 82.0 +/- 12.4h (P < 0.05), for T1 and T2, respectively. The ovulation number, diameter of ovulatory follicle (mm) and the ovulatory follicle growth rate were 1.2 +/- 0.45 and 2.33 +/- 1.03 (P < 0.05), 8.4 +/- 2.4 and 6.2 +/- 0.1mm (P < 0.05) and 2.4 +/- 0.97 and 2.9 +/- 1.67mm (P > 0.05) for T1 and T2, respectively. The use of sponge and CIDR-G (R) associated with the CE was effective in inducing estrus. The complete absence of luteolysis at the moment of the device withdrawal, showed a great variation for the studied traits. Devices using natural and synthetic progesterone should be maintained on place for at least seven days when associated with 1 mg of CE.