7^th International Veterinary Congress

In the vast majority of equine embryo transfer programs, flushing takes place on days 6, 7 or 8 post ovulation. In the present study, embryos could, instead, be obtained on days 10-11 after ovulation. For this purpose, 36 Arabian mares (7-24 years old) were used as donors for embryos and 6 mares were kept as control. Of the 36 donor animals, 2 mares died suddenly and flushing was carried out after excision of the uterus.

Recipient mares (N=70) aged 5-10 years, and were kept in embryo transfer facility. The degree of synchronization was -4 to -6 days.

The procedure used depended on flushing of the donor mares after detection of embryonic sac using ultrasonography. Large pore AI catheters and external sheath of double guarded uterine swabs were used in the process of embryo transfer. A controllable manual pipette was used in the control process of loading, washing and transfer. This method overcame the problem of burst of large embryos.

A high recovery (94.4%) and pregnancy (73.5%) rates could be obtained. Results have also shown that higher pregnancy rate was obtained with recipient mares on day 4 post ovulation, whereas lower pregnancy rates was found in recipient mares on day 6 post ovulation.

In conclusion, this study demonstrated that there was a possibility of embryo transfer on day 10-11 post ovulation i.e. after embryo detection with ultrasound scanning. This method permits flushing of mare's uterus after death on 10-11 days of pregnancy for maximum exploitation of the donor mare. Furthermore, concerning mares with a history of low embryo recovery flushing did not take place until the embryo was detected with ultrasound so as to save flushing media and number  of flushes.