Fatores que afetam a fertilidade em programa de transferência de embriões equinos

Abstract

Assisted reproduction by means of embryo transfer (ET) provides the production of foals with the objective of honing the descendant animals to perpetrate good traits. Embryo transfer is a technique that allows the increase in the number of births per year of a mare, being that knowing the effect of variables involved in the process is vital to improving the results. The objective of this work is to analyze information on the aspects connected to the fertility in ET programs for equine conducted over 10 years of work. General and reproductive data of 150 embryo donor mares, 362 recipients and 73 stallions of many breeds were submitted to statistical analysis using the SAS® packet (Cary, NC – USA). The proportion of pregnant recipients was the dependent variable, being the effects of age, breed, dominant follicle diameter (DFD) and ovulation induction, in the scope of the donors, stallions and recipients, analyzed by chi-square. The gestation rate was more elevated (P<0.05) for embryos transferred from donors of the Campolina breed when compared with the others (74.0 vs 57.6%, respectively). The rates of positive washed of 50.2%, 58.97% and 53.16% were similar (P=0.45) between the age classes of ≤ 7 years, > 7 < 12 years and ≥ 12 years, respectively. Concluding, the donor breed, 73%; the non-ovulation induction, 73% and the use of frozen/thawed semen of 28.57% were factors that influenced the gestation rates on the conditions of the present experiment. It becomes clear that, in ET programs for equine, the presence of a stallion in the Horse Farm has the potential to improve gestation rates. Additionally, the field technicians might deepen the data collection, since it became evident that many easily obtained variables that would be useful might have complemented this work.