The aim of this study was to evaluate the effect of GnRH, hCG and eCG applied 14 days after fixed time artificial insemination (FTAI) on the rate of pregnancy and embryonic and foetal survival in cows under heat stress. The cows (n = 234) were synchronized, inseminated and received 14 days later via i.m. the hormonal application: a) Control group: 2 ml of saline solution (n=56), b) GnRH group: 100 µg of GnRH (n=58), Group c) hCG: 1500 IU of hCG (n=60), and d) ECG Group: 400 IU of eCG (n=60). The diagnosis of pregnancy and the evaluation of the number of corpora lutea (CL) was determined by ultrasonography on days 34, 45 and 60 of the AI. Cows treated with GnRH had a higher pregnancy rate (p<0.05) and no significant differences were found between the other groups. Embryonic and foetal survival between days 45 and 60 was constant in all groups, but one foetal death occurred in the eCG ...

The aim of this study was to evaluate the effect of GnRH, hCG and eCG applied 14 days after fixed time artificial insemination (FTAI) on the rate of pregnancy and embryonic and foetal survival in cows under heat stress. The cows (n = 234) were synchronized, inseminated and received 14 days later via i.m. the hormonal application: a) Control group: 2 ml of saline solution (n=56), b) GnRH group: 100 µg of GnRH (n=58), Group c) hCG: 1500 IU of hCG (n=60), and d) ECG Group: 400 IU of eCG (n=60). The diagnosis of pregnancy and the evaluation of the number of corpora lutea (CL) was determined by ultrasonography on days 34, 45 and 60 of the AI. Cows treated with GnRH had a higher pregnancy rate (p<0.05) and no significant differences were found between the other groups. Embryonic and foetal survival between days 45 and 60 was constant in all groups, but one foetal death occurred in the eCG ...

The objective of this study was to evaluate the in vitro embryo production rate up to the blastocyst stage with two fertilization media: FERT-TALP and modified TCM-199, grown in BOEC medium, from oocytes collected by aspiration of follicular ovaries of creole cows obtained from the slaughterhouse. In total, 281 oocytes were collected, 179 for FERT-TALP medium and 144 for modified TCM-199. The oocytes were subjected to the process of maturation, fertilization and embryo culture in vitro. An oocyte cleavage rate of 25.8% was obtained in FERT-TALP and 2.4% in modified TCM-199 at 18 hours post-fertilization. Likewise, at 48h, 87.7% of total cleavage was obtained in FER-TALP and 40.5% in modified TCM-199, whose percentage of embryos with 4 to 8 cells was 64.5 and 26.2%, respectively. In the morula and blastocyst phase, a rate of 10.3 and 3.9% was achieved in FERT-TALP, respectively, while non...