What is embryo transfer (ET)?

We can inseminate your valuable competition mare and 7 9 days later we can flush the early embryo (blastocyst) from her uterus and transfer it by a process called embryo transfer (ET) into the healthy uterus of a recipient (surrogate) mare.

Advantages of ET:

ET enables the embryo donor mare to continue her competition career while the recipient mare carries the pregnancy to term.
It is possible to obtain more than one pregnancy per year from a mare. You may choose to inseminate your mare with the same stallion each time or use different sires for each estrous cycle. We usually recommend that you aim for 1 3 pregnancies from each donor mare each season.
If you have a mare with an old, subfertile uterus who is prone to losing pregnancies after 15 days then it is beneficial to transfer her embryo into a healthy uterus of a younger mare.
The fertility of an embryo transfer programme is similar to a normal breeding programme.
The whole procedure is non-surgical
There is no increased risk of embryo loss or birth defects from ET foals than from foals in the normal population.
New embryo freezing technologies enable us to achieve satisfactory pregnancy rates from frozen-thawed embryos.

Disadvantages of ET:

It is more expensive that conventional breeding programmes.
The procedure requires considerable skill and experience in meticulous embryo handling procedures.
The synchronisation of recipient mares is challenging (but fun!) and therefore 2-3 embryo recipient mares are required for every donor mare. This does contribute to the cost of the programme.

The results of embryo transfer:

We recover embryos from >70% of cycles. The embryo recovery rate is however, dependent upon the fertility of the mare and the stallion and whether fresh or frozen semen is used.
Of all the (Grade 1) embryos recovered we achieve 75-80% embryo survival after embryo transfer. In the 2008/9 season was had a record year with more than 93% of embryos surviving after transfer! Based on our excellent results we offer a pregnancy guarantee invoicing scheme. Contact us for details:)
This gives us a 55 60% per cycle pregnancy rate.
Therefore, it is recommended that you budget for 2 cycles per pregnancy.


The key to the success of the ET programme is to provide good recipient mares that are settled in their routine. To optimise the fertility of the recipients they should ovulate the day after the donor mare and therefore we require 2 recipients for every donor mare for each cycle. The recipient mares should be fertile and between 3 and 12yo, they can be provided by the mare owner or by EquiBreed NZ Ltd. The donor mare can reside at EquiBreed NZ Ltd or carry on competing. However, the recipient mares need to board at EquiBreed NZ Ltd to settle and be managed closely. If you are using frozen semen for artificial insemination, to maintain goodwill, it is recommended that you contact the stallion owner to let them know that you are using the semen in an ET programme. Please do not hesitate to contact us if you have any further questions about your breeding programme.

Copyright ©Lee Morris, A harnesslink.com hosted website
Best viewed at IE6 running at 800x600 or greater