Reproduction > Embryo Transfer

Embryo Transfer

An Overview

Equine embryo transfer is an assisted reproductive technique that provides new
opportunities to the horse breeder.  This procedure involves removing a very young (7-8 day) embryo from a valuable donor mare and transferring it into the uterus of a recipient mare to complete development. 

Although the foal is born and nursed by the recipient mare, it is the genetic offspring if the donor mare.  Some reasons this may be desirable include:
1. Increased number of offspring from valuable mares
2. Sub-fertility of donor mare due to inability to
carry a pregnancy to term
3. Production of foals from competitive mares with minimal training impact
4. Production of foals from late foaling mares

The Procedure

Donor Mare- Initially, we treat the donor mare in a similar manner to any other breeding mare.  Her cycle is monitored by rectal/ultrasound examination and breeding is timed according to these findings.  Seven or eight days after ovulation is detected, we place a catheter into her uterus and the embryo is removed by a flushing technique that utilizes a special fluid.  The microscopic embryo is then located in the flush fluid and is prepared for transfer.

Recipient Mare- The recipient mare is the mare into which the embryo will be placed for complete development, birth and nursing.  The recipient mare, which should be young and reproductively healthy, must ovulate in a 48 hr. window following the donor mare.  Should you own a suitable recipient mare, her cycle can be medically manipulated to encourage her to ovulate in this time frame.  If your proposed recipient mare does not ovulate in the appropriate window, a mare provided by Kleinpeter and Cramer Equine Veterinary Services, LLC will be available as an alternative.  If you do not own a suitable recipient mare, a Kleinpeter & Cramer mare can be you primary option.  Once the pregnancy is established, you will lease this mare for the duration of pregnancy through weaning of the foal.

Success Rates

Collection rates of equine embryos vary greatly according to the reproductive health of the donor mare.  Young, healthy mares with no history of reproductive problems typically provide embryo recovery rates near 80%.  Successful embryo recovery from older, sub-fertile mares varies greatly with the individual, but is near 30% as a group.

Once the embryo is successful recovered, transfer rates are approximately 80% for high quality (grade I & II) embryos.  A 10% pregnancy loss during the first 50 days of pregnancy corresponds to the average pregnancy loss due to naturally occurring maternal and/or fetal problems.

Embryo Transfer Programs: If you are considering your breeding options for the spring or would like to know more, please view the Embryo Transfer Programs that we offer or contact Dr. Eddie for more information.

You can view and submit our Embryo Transfer Agreement Forms online or download a .pdf copy.