Synchronization of estrus using CIDR, FGA or MAP intravaginal pessaries during the breeding season in Nubian goats

During the breeding season (Autumn) 60 Nubian does were allocated to groups for estrous synchronization, using intravaginal pessaries impregnated with fluorgestone acetate (FGA; n = 20), medroxyprogesterone acetate (MAP; n = 20) or controlled internal drug release devices (CIDR; n = 20). All intravaginal progestagens were administered for a period of 13 days. At pessary removal all does were injected with 5mg prostaglandin F-20 . Estrous detection was done using two vasectomized bucks. Goats were intra-cervically inseminated with fresh, diluted and cooled semen at 12 and 24 h after onset of estrus. Estrous response for all treatments groups was 100%. The onset of estrus for the CIDR, FGA and MAP groups was (mean±S.D.) 40.2±10.5, 32.9±9.7 and 48.8±12.0 h, respectively. Onset of estruswas shortest in theFGAgroup (32.9±9.7), compared to the MAP (P < 0.01) and CIDR (P < 0.05) groups. In the CIDR group onset to estrus (40.2±10.5) was shorter than in the MAP group (P < 0.05). The induced estrous duration for the CIDR, FGA and MAP groups were 39.2 ± 10.9, 43.8±13.8 and 40.0±11.3 h, respectively. Kidding percentage recorded following AI in the CIDR, FGA, andMAPtreatments was 63, 65 and 63%, respectively. The use of FGA and MAP sponges and CIDRs with prostaglandin F-2 administration at the time of pessary removal induced an efficient estrous response and acceptable fertility. The use of CIDR can be considered a worthy alternative to replacing intravaginal sponges for estrous synchronization during the breeding season in Nubian goats. © 2004 Published by Elsevier B.V.