Recovery rate and morphologic features of cross bred embryos (Equus caballus x Equus)

Production biotechnologies, particularly embryo transfer (ET) has constantly been contributed to reproduce horses and other species. The mules market has shown continuous growth, however, the biotechnology for mule assisted reproduction is still scarce. The aim of this study was to evaluate the embryo recovery rate and the features of the embryos from mares bred with donkeys. The embryos recovery attempts were performed on days 6 to 9 after ovulation, in order to evaluate the embryo recovery rate and the features related to age, morphology and embryonic diameter in each day. The overall embryo recovery rate was 55,9% (71/127), and there was no significant difference (p>0,05) on different days (D6-D9). Embryos were recovered in stages of morula, early blastocyst, blastocyst and expanded blastocyst. The diameter of the embryos ranged from 147-1688 mu m and the mean diameter of all the embryos collected was 438,04 mu m. The collection of hybrid embryos might be performed between days 6 and 9 after ovulation, and provides recovery of embryos in the early stages of development.