Utilização de PGF2alfa como indutor de ovulação em programas de inseminação artificial em tempo-fixo com novilhas púberes.

Abstract

In the field of animal production, the success and profitability of a beef farm is directly related to the reproductive performance commercial herd, must seek viable alternatives to reach an array producing one calf per year for it appeared artificial insemination techniques in fixed time (TAI). Many protocols are used for TAI technique and the use of prostaglandin F2a to induce ovulation in these protocols has been studied.The objective of this study was to evaluate the effect of prostaglandin F2α (PGF) on ovulation and pregnancy rate in timed artificially inseminated pubertal heifers.Was used 461 pubertal beef heifers, 12 to 14 mo of age were used. On Day 0, all cattle were given an intravaginal progesterone-releasing device (DIB) plus 2mg benzoate estradiol (BE) intramuscular. On Day 9, DIB was removed and were given 500 μg im of PGF. Heifers were randomly assigned to one of three treatment groups and were given; 1) 1mg of EB (EB Group; n = 151); 2) 500 μg of PGF (PG group; n = 150), 24 h after DIB removal, and 3) 300 μg of Estradiol Cipionate (ECP Group; n = 160) at DIB removal. The TAI was performed 48 hours after DIB removal in ECP group and at 54 h in PG and EB Groups. Percentage of heifers ovulating tended to be higher in the PG group than in the other groups (P = 0.08). No difference was detected on the pregnancy rate among groups (P = 0.9).The results suggest that the use of PGF as ovulatory stimulus resulted in synchronized ovulation and similar pregnancy rate compared to ECP and EB in cattle subjected to TAI programs.