Embryo Transfers

What is embryo transfer and why do it?

 The Embryo Transfer begins with breeding the donor mare (the mare    that is "donating" the embryo).  Bred as usual, she is monitored with daily untrasounds to establish the exact ovulation date, the date her egg is released.

 Embryo transfer involves removing the embryo from the uterus of the donor mare 7 days after she was bred and ovulated. The embryo is placed in the uterus of a recipient mare that also ovulated 7 days ago.  The embryo becomes a foal that develops in the recipient mare. When the foal is born, it retains the DNA of the original donor mare and the stallion to which she was bred. 

Ideal Embryo flushed at 7 days.

 Seven days after the ovulation date the donor mare's uterus is flushed. The fluid from her uterus is run though a special filter cup designed to isolate the embryo.
The flushed fluid is thoroughly searched for an embryo under a microscope. 
 A 7-day embryo is approximately ¼ to ¾ millimeter in size. It is just visible to the naked eye.
 The embryo is promptly transferred into a waiting recipient.
 Now we can also freeze the embryo.  This allows many other options for timing and marketing.  You can sell the frozen embryo and ship it, instead of the foal itself.

 Young  mares still competing,  old mares that cannot carry a foal, valuable mares that you want to market more than one foal per year, trying to prove a young stallion by breeding multiple times to a good mare, and banking many foals from an older mare are all reasons for embryo transfer.  

Dr Shelly O'Connell DVM