Reemplazo parcial de la hormona folículo estimulante porcina (FSH-p)por gonadotrofia coriónica equina (eCG) en la superovulación de vacas en producción

Abstract

Milk production is of great importance to the national economy. Through superovulation and embryo transfer it is possible to obtain genetically improved animals, and therefore improve the productivity of dairy farms. The objective of the present study was to evaluate the effect of substituting the last four doses of FSH in the superovulation protocol for two doses of eCG in dairy cows. Eight Holstein cows were subjected to a protocol of follicular wave and ovulation synchronization, and ovarian stimulation. Cows were randomly assigned to one of the following two superovulation treatments: FSH, 8 decreasing doses of FSH for 4 days; FSH + eCG, the last four doses of FSH in the conventional protocol were replaced by a 600 IU dose of eCG. The data were analyzed by analysis of variance of the SPSS statistical program. The ovulatory response was similar between treatments (10.25 ± 1.31 and 10.00 ± 1.29 for FSH and FSH + eCG respectively). The cows treated with FSH (6.00 ± 0.58) had a higher number (P0.05) of anovulatory follicles than the FSH + eCG (3.25 ± 0.63). The number of recovered structures, transferable embryos, degenerated embryos and unfertilized oocytes were similar between treatments. In cows treated with FSH + eCG, more morulae (45.6 vs 20.1% respectively) and expanded blastocysts (6.8 vs 0.0% respectively) and fewer regular blastocysts (40.7 vs 6.6% respectively) were recovered than FSH treatment, although differences were not significant. Cows treated with FSH produced fewer quality 1 and more quality 2 blastocysts than FSH + eCG treated cows. In conclusion, substituting the last four doses of FSH in the conventional superovulation protocol for one dose of eCG did not improve the superovulatory response or the production of transferable embryos.

Keywords: multiovulation, embryo transfer, FSH, eCG, dairy cows.