Ms. Gottfried

Embryo Transfers in Mares

The process of removing an embryo from a mare (donor mare) and inserting it into a recipient mare .

What is it?

ET enables the embryo donor mare to continue her competition career while the recipient carries the pregnancy to term.

It is possible to have more than one foal per year, from different sires with the same mare.

If a mare is difficult to have hold a pregnancy, this can increase the cases of a foal.

Non-surgicalCan freeze embryos with the same success rate as

normal ET.Can breed younger mares that are not yet ready to

have a foal.

Why use it?

More expensive Requires skill and experience in meticulous

embryo handling procedures.The synchronization of recipient mares is

challenging and generally requires 2-3 recipient mares for every donor mare.

Low success rate.Some breed registries will not recognize it, or

will with more money towards DNA testing.

Why to NOT use it?

Successful reproductive historyModerate to good body conditionPhysical examinationNormal heat cycle based on teasing,

palpation and ultrasound.Should have foaled at least two months prior.Generally an easy to handle mare.

What to look for in a donor mare?

3-10 years oldGood physical health and good weightReproductively normal based on a rectal

palpation, ultrasound, uterine biopsy, culture and cytology.

Should have a 30 mm CL and no fluid in the uterus.

Should have a tight cervix.

What to look for in a recipient mare?

Surgical or Non-surgical

Options

The donor mare is bred and ovulation confirmed by ultrasound.

7 days after OVULATION: embryo is still too small to be seen my ultrasound.

Mare is put in stocks with tail tied and washed.

Foley Catheter is put into the uterus (cervix is closed) and the balloon is inflated.

How does it work?

Two people are needed at this point, one to hold the catheter and one to add and drain the fluid.

Fluid is a modified saline solution Fluid is guided in the uterus using gravity.Generally one liter at a time is used, and after

it enters the uterus, it is emptied using gravity through a filter.

Important not to let the filter dry out.

How it works

The filter is looked at under a microscope until the embryo is found (if one exists)

The embryo is then washed in a sterile solution to help it maintain itself.

Then using A.I. the embryo is inseminated into the recipient mare.

If all goes as planned, 340 days later a beautiful foal will be born!

What happens next?