The Equine Fertility Clinic at Warren House Farm is one of the few Veterinary Clinics in Britain that regularly and successfully carry out this exciting procedure. This service is run by John Newcombe and his colleague Greg Staniek from Bourton Vale Equine Clinic.

John, as founding partner of Newcombe and East Veterinary Surgeons (now Warren House Veterinary Centre), is one of Britain’s most prominent stud vets. He has a wealth of experience in all aspects of mare fertility that few people in this country can match.

Our practice has offered an embryo transfer service for 11 years. After mixed success in the first few years it is now highly successful and is considered a routine procedure . During the breeding season we may carry out up to 3 embryo transfers in a week.

Picture of 7.5 day equine Embryo (0.25 mm diameter)


Embryo transfer, as its name suggests, is taking a 7 day old embryo from one mare (the “Donor”) and placing it into the uterus of another mare ( the “Recipient”). This recipient mare will then carry the pregnancy to term and subsequently mother the foal until weaning. The donor mare (no longer pregnant) is then free to be mated again in order to achieve more pregnancies in the same year or to continue her competitive career.

Searching for Embryo using Stereo Microscope)


Embryo transfer opens up a number of opportunities to horse owners that could not have been previously achieved.

    These include:
  • More than one foal in one breeding season.
  • Competitive career can be maintained while still being able to produce foals every year.
  • Allows for mares with problems that would prevent them carrying a foal to term (eg.age related uterine degeneration, injuries) or have abnormalities that would prevent a normal birth (e.g narrow/small pelvis, rupture of the abdominal muscles) to produce pregnancies each year.

Ultrasound Picture of 16 Day Equine Embryo


In order to carry out this procedure the Donor mare is mated or inseminated and the precise time of ovulation is ascertained by regular ultrasound examination of her ovaries. The Recipient (one of your own mares or a mare from the Clinic’s pool of recipient mares) must be at the same stage of her reproductive cycle (ovulated within two days of the Donor mare’s ovulation).

Seven days after the time of the donor’s ovulation both mares (Donor and Recipient) must be brought to our Fertility Clinic. There the uterus of the donor mare will be flushed out using a special embryo flushing medium. This flushing medium is recovered from the uterus, filtered and examined under the microscope for the embryo.

Once found, the seven day embryo (which at this stage is no more than ¼ mm in size and barely visible to the naked eye!) is checked for normality, specially prepared by washing and then transferred to the uterus of the recipient mare.

The recipient mare can then be ultrasound scanned 6-7 days after the procedure to confirm pregnancy (at which time the embryo will be 5-15mm in diameter). Further ultrasound scans are usually advised to check for normal development of the pregnancy.

Ultrasound Picture of 21 Day Equine Pregnancy


For further information about our embryo transfer service please feel free to contact the clinic and ask to speak to John Newcombe.

Ultrasound Picture of 26 Day Equine Pregnancy