Embryo Transfer


Embryo transfer is becoming increasingly popular as a tool in equine reproduction and this technique is routinely used at our Equine Breeding Centre with considerable success.


Susanne Brundell & broodmares at her property at Pilton




  • Performance mares can produce foals from as young as two years old while continuing their performance career.


  • Enables production of foals from older or unsound mares or mares with a history of pregnancy loss (resorption or abortion). In reality these mares may not be ideal donors, as embryo recovery can be as low as 20% per cycle especially in agedmares. The quality of the unfertilized egg determines the quality of the embryo. As with any female mammal the percentage of less viable eggs increases with age.


  • If a mare foals late in the season (e.g. January or February), embryo transfer can be used to produce a foal in the current season using a recipient and enable the mare to start early in the following season.


  • Allows production of more than one foal per mare per year. It is feasible for mares to produce several foals in a season, although some breed societies have restricted registered offspring to one per mare per season.



 If the donor mare is reasonably fertile & the semen from the stallion is of good quality, youfig4lg can expect:

  •   At least 75% of normal donor mares to with fair to good semen to conceive.


  •   Embryo recovery to be  successful in around 75% of cases.


  •   Assuming an embryo is recovered, transfer to the recipient should be successful in approximately 80% of cases.. 


Embryos are not guaranteed with every flush. The international standard success rate is 2 cycles per embryo retrieved in reproductively normal mares given good semen.  Of course, some mares occasionally or consistently have double ovulations that occur at the same time and these cycles can produce 2 embryos per flush.  et33fig3lg

NB. Embryo recovery rates depend on the fertility of the mare and the quality of semen.



The donor mare must be synchronised with a suitable recipient mare.  The recipient should be a maiden or a highly fertile proven foal producer of less than ten (10) years of age.  The recipient must be synchronised to ovulate at a certain time after the donor. This requires synchronisation of several recipients to ensure that at least one will be suitable.  The Equine Breeding Centre keeps a herd of recipient mares for this purpose.

 The donor mare should be scanned to determine the optimum time of service and can then be served naturally or inseminated with fresh, chilled or frozen semen.  Fertilisation should occur and the fertilised egg will remain in the oviduct for six (6) days before descending into the uterus.  It can then be flushed from the uterus (usually between  6 ½ & 7½ days depending on mare & semen factors) and transferred immediately into the recipient, non-surgically (similar to AI).

The recipient mare can be examined by ultrasound for pregnancy on day 14 (seven days after transfer). Some pregnant recipients may be maintained on a hormone (RegumateP) for up to 60 days after transfer, however in most cases the RegumateP may be stopped at 22 days of embryo age.


  Australia’s first vitrified frozen embryo foal – produced at Wilson’s Equine Breeding Centre. 


                        Robyn & “Frosty”  Branigan’s Pride R.I.D. (Ire) / Maganey

The embryo (Frosty) was frozen for 6 weeks, transferred to a recipient and was born on 23rd November 2007. 



Routinely, embryo transfer procedures are offered from the end of September as this allows a large number of recipient mares to be cycling properly. Clients requiring embryo transfer in early September should contact the office by mid June as the most forward recipients will need to be placed under an artificial lighting regime along with an increased rising plane of nutrition.  The donor mare will also need to be placed under lights too and this treatment will need to start by mid-June.   The donor mare can be placed under the appropriate lighting regime at the owner’s address until late August.  We try very hard to keep the costs down for this procedure, but an additional charge is applied to donor mares requiring ET in early September. If you are interested, please contact the office on or email us () by mid-June so that we can arrange an appropriate regime.



Bookings must be made early in the season.

The Lease Fee for the recipient mare entitles you to take the mare home and keep her until the foal is weaned. A portion of the lease fee is refundable when the mare is returned to the Equine Breeding Centre, however she must be in similar body condition and in normal reproductive health. If the recipient mare is not returned a suitable replacement mare (under 10 years of age, easy to catch and in good reproductive health and body condition) may be substituted by the owner of the donor mare OR the bond may not be refunded.



For practical reasons, embryo transfers are only done at the Equine Breeding Centre and the recipient should remain there until at least twenty-eight (28) days in foal. Please note you will be required to pay agistment for the recipient mare also, regardless of whether it is owned by you or the Equine Breeding Centre.  Agistment charges for recipient mares owned by the Equine Breeding Centre commence from the time an embryo is recovered and transferred into the synchronised recipient.

A deposit is required when the mare is admitted to the Equine Breeding Centre.

 PRICING INFORMATION - Please contact the Equivet office



Mares & foals at the Spring at Equivet Breeding Centre

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