Fixed Time Artificial Insemination in buffalo using different estrus synchronization protocols

The objective was to demonstrate the efficacy of ear implant and intravaginal progesterone device to synchronize estrus in female buffaloes (n=180) and use fixed time artificial insemination (FTAI) associated or not to GnRH. The buffaloes were raised and grazed in rotational artificial pastures supplemented with a commercial mineral mixture and water supplied ad libitum. Four groups with 45 females were established: group (G1) and G2 received ear implant, and beside that group G2 received 1 ml of GnRH (i.m.) at the time of insemination; group 3 and 4 received vaginal implant and group 4 was received 1 ml of GnRH i.m. at the time of insemination. Females were inseminated 60 hours after with drawal of progesterone implant. The protocol efficacy, for GnRH use, type of implant and the AI technician cleverness on pregnancy rates were evaluated and compared. Data collected were analyzed by chi-square statistical test, with 5% significance. The overall pregnancy rate was 46.6% (84/180), and 40.0%, 60.0%, 53.3% and 33.3% for G1, G2, G3 and G4 respectively, with statistic difference for pregnancy rate between G2 and G4 (P 0.05) between G2 and G4 pregnancy rate of 46.67% (42/90). Regarding the type of implant on pregnancy rate it was 50% (45/90) and 43.33% (39/90) respectively, also without any statistical difference (P>0.05), however the AI technician cleverness influenced the pregnancy rate (P