Uso do cipionato de estradiol na indução da ovulação de búfalas criadas em várzea da região de Itacoatiara, Amazonas

Abstract

The objective of this study was to determine the efficiency of estradiol cypionate (CE) as an ovulation inducer in a fixed-time artificial insemination protocol in buffaloes managed in floodplain areas of Itacoatiara, Amazonas, Brazil. A total of 69 crossbred buffalo cows were selected and distributed into two allotments. In the first allotment, 39 females received a new progesterone intravaginal device (P4; 1.0g) and 2.0mg im of BE, on D0. On D9 the intravaginal device of P4 was removed and 0.53mg im of PGF2α and 400UI im of eCG were applied. The buffaloes were randomly divided into two groups: the GCE (20 cows) that received 1mg of EC on D9, and the GBE group (19 cows) that received 1mg of BE 24h later, on D10. In D11, all females were submitted to IATF 56h after the removal of the intravaginal P4 implant. The same methodology was used in the second allotment, where 30 females were distributed into GCE (14 cows) and GBE (16 cows). To assess follicular dynamics, the diameter of the largest follicle in the ovary of 11 buffaloes per treatment was evaluated at D0 and D9 at D12 (24-hour interval) by ultrasound. All animals in the experiment were submitted to ultrasound to diagnose pregnancy more than 30 days after artificial insemination. There was no difference (p>0.05) in follicular diameter (9.6 ± 0.89mm vs. 10.7 ± 1.12mm; p = 0.06), in the ovulation rate (90.9% vs. 90, 9%; P = 1) and pregnancy rate (58.8% vs. 62.9%; p = 0.79), however, buffaloes from the GCE treatment have less time between P4 removal and ovulation when compared to GBE buffaloes (37.4h vs. 52.8h; P = 0.001), respectively. Thus, it was concluded that the implantation of the IATF in the Amazon floodplains is feasible and that the use of the EC on the day of removal of the P4 intravaginal implant results in responses similar to the BE, being more advantageous since it reduces the number of managements and the expenses with the labor.