Reproductive parameters of Mangalarga Marchador mares in commercial project of embryos transfer / Parâmetros reprodutivos de éguas Mangalarga Marchador em projeto comercial de transferência de embriões




It was objectified with this study to characterize and evaluate the reproductive efficiency in donor and recipient mares of Mangalarga Marchador race in commercial programs of Embryos Transfer (TE) and verify the relationship of some reproductive characteristics, zootechnics and methodology in the TE among conception rates in recipients. Data collected in four different farms, from 1998 to 2004, were analyzed where 1141 crops were accomplished with recovery of 830 embryos. The percentile of embryos recovery found because of the number of crops of the six reproductive seasons was 72.74%. Differences were not observed among the rates of embryonic recovery in the different reproductive seasons (P>0.05). Generally, 90% of the recovered embryos were 8 to 9 days of age. There was no difference among the embryonic recovery from the first to the ninth embryos crop of the reproductive season, as well as among mares inseminated during the colt heat and another subsequent heat (P>0.05). The size of the first follicle and the donor s artificial insemination in preovulatory phase were the characteristics that presented positive correlation with the embryonic recovery in donors (P<0.05). The conception rates observed in the sum of all of the seasons in 15, 30, 45 and 60 days were 73.4; 69.9; 66.7 and 64.46%, respectively. The early embryonic losses between 15-30; 15-45 and 15-60 days were 4.8; 9 and 12.15%, respectively, not differing among the seasons (P>0.05). Differences were not observed in the conception rate and early embryonic loss in the embryos transferred immediately after the crop (66.8 and 13.5%) and embryos transported at room temperature for periods inferior to 1 hour (62.9 and 14.4%) (P>0.05). A correlation was not observed between the studied variables and the conception rate in the recipients (P>0.05). Regarding the rate of early embryonic loss, there was no difference among the different intervals of ovulations synchrony among the donors and recipients (P>0.05). Related to the conception rate, better results were verified in the intervals of -3 and -2 days regarding the ovulations synchrony of donors and recipients (P <0.05) and the smallest rates in the intervals of -6 (P <0.05) with intermediary values in the intervals of -1, 0 and +1, although the last two didn t differ of the interval -6 (P>0.05). The use of that flexibility in the technique provides advantages for commercial programs of equine embryos transfer, making possible the optimization in the use of recipient mares, costs reduction and improvements in the farms management.


reproducao animal equine embryos transfer transferência de embriões reproduction equino reprodução

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