Intratubal transplantation of early canine embryos

It has been reported previously that intrauterine transplantation of canine embryos is possible. In this study, the possibility of intratubal transplantation of early canine embryos was investigated. Beagles at ovulation +/- 1 day estimated from peripheral blood progesterone concentrations were used as embryo donors and recipients. The Beagles (n = 13) were mated 1-4 days after ovulation and embryos were collected 1-3 days after mating (3-7 days after ovulation) by tubal flushing or salpingectomy. Embryos were transplanted using a glass tube or catheter into the upper or lower uterine tubes at 1.5 and 5.0 cm from the fimbriae tubae, respectively. The mean embryo yield from three bitches from which embryos were collected by tubal flushing was 28.2%. Embryos collected from ten bitches by salpingectomy were at the syngamy to eight-cell stages of development, and the mean yield was 95%. Embryos (1-7 per bitch) were transplanted into the upper uterine tube of seven recipient bitches and to the lower uterine tube of eight recipient bitches. It was found that no bitches in which embryos were transplanted into the upper uterine tubes became pregnant, whereas four bitches (50%) in which embryos were transplanted into the lower uterine tubes became pregnant (P < 0.05, chi-squared test). The success of embryo transfer was not affected by differences in embryo stage or day of ovulation. In conclusion, it is possible to impregnate bitches by transplanting early canine embryos into the lower uterine tubes.