Table 5.
Ovulation, conception, and pregnancy rates of Bos indicus pubertal heifers (Study 1) and nonlactating cows (Study 2) submitted to a synchronization of ovulation protocol using progesterone associated with estradiol having different strategies to improve fertility. Adapted from Peres et al. [53].
| Item | Ovulation rate | Conception rate | Pregnancy rate |
|---|---|---|---|
| Study 1-CIDR uses and eCGa | |||
| CIDR 1st use/0 IU eCG | 84.3% (161/191) | 49.1% (79/161) | 41.4% (79/191) |
| CIDR 1st use/200 IU eCG | 89.9% (169/188) | 51.5% (87/169) | 46.3% (87/188) |
| CIDR 1st use/300 IU eCG | 94.6% (177/187) | 52.0% (92/177) | 49.2% (92/187) |
| CIDR 3rd use/0 IU eCG | 83.4% (176/211) | 49.4% (87/176) | 41.2% (87/211) |
| CIDR 3rd use/200 IU eCG | 87.2% (170/195) | 54.7% (93/170) | 47.7% (93/195) |
| CIDR 3rd use/300 IU eCG | 93.9% (170/185) | 47.1% (80/170) | 44.2% (80/181) |
| Study 2-Time of PGF2α treatment and eCGb | |||
| PGF2α d 7/0 IU eCG | 80.3% (143/178) | 59.4% (85/143) | 47.7% (85/178) |
| PGF2α d 7/300 IU eCG | 90.7% (156/172) | 62.1% (97/156) | 56.4% (97/172) |
| PGF2α d 9/0 IU eCG | 64.4% (112/174) | 42.0% (47/112) | 27.0% (47/174) |
| PGF2α d 9/300 IU eCG | 89.3% (159/178) | 50.9% (81/159) | 45.5% (81/178) |
aPubertal heifers received a nonpreviously used CIDR (1st use) or a CIDR used previously for 18 d (3rd use) at initiation of a TAI protocol, and 0, 200, or 300 IU of eCG on d 9 relative to CIDR insertion, in a 2 × 3 factorial design. There were effects of eCG treatment on ovulation, conception, and pregnancy rates (P < .05).
bNonlactating cows were treated with 12.5 mg of dinoprost tromethamine on d 7 (48 h before CIDR withdrawal; PGF2α d 7) or on d 9 (immediately after CIDR withdrawal; PGF2α d 9), and 0 IU of eCG or 300 IU of eCG on d 9 of an ovulation synchronization protocol. There were effects of time of PGF2α treatment on ovulation, conception, and pregnancy rates (P < .05); eCG affected ovulation and pregnancy rates (P < .05).