# Embryo Transfer



## bubba13 (Jan 6, 2007)

Firstly, we were curious as to the process involved in 'harvesting' (correct term??) a mares eggs. 
*I'm no expert either, but I've assisted in several, so let's see what I can answer...*
How many do the get at one time? *just one*
How they collect them? *you impregnate the mare with the usual process (generally AI, probably with hormone cycling to time it perfectly), then "flush" the embryo*
How do they store them? *in a Petri dish, as you correctly guessed*
How long they can be stored? *I believe it's generally just short-term, to check for grade and viability, and then they are implanted in the recipient mare soon after*


How do people choose a surrogate mare? Is is simply a matter of convenience, or is there a lot more thought involved (ie, mares conformation, size, previous breeding history, temprement etc) (I'm assuming its the second one, but you never know!) *well, you wouldn't want an itty bitty mare or one with wonky hips, but other than that, I've never seen conformation or size be a concern; she must be at least halter broke and easy to work around, but that's about it--and I've seen them use both maiden mares and proven mommas*


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## Avalon Equine (May 26, 2011)

OTTBLover said:


> Firstly, we were curious as to the process involved in 'harvesting' (correct term??) a mares eggs.


In the equine, harvesting a mare's eggs is a surgical procedure. I think you are looking at harvesting the embryo, or flushing the embryo is more commonly the term used.



> How many do the get at one time?


The equine is difficult to "super ovulate". Most other mammalian species can be hormonally manipulated to produce multiple embryos. With the equine, even using eFSH (equine follicle stimulating hormone) it only doubles your chances. The industry average for flushing embryos is 50% - so 50% of the time, you will flush an embryo...with the use of eFSH, you double your chances to, drum roll please...1.



> How they collect them?


The mare's uterus is filled with a flush media that is specifically formulated for doing embryo transfers. The flush is then run back through a catheter that has a filter attached that will capture the embryo. The fluid that is in the filter is then viewed under a microscope and the search begins .



> How do they store them?


In most cases, the embryo is immediately transferred into a recipient mare. However, there is now a procedure where the embryo can be frozen and stored. Success rate of transferring the thawed embryo into a recip mare is comparable to those of embryos that are transferred immediately.



> How long they can be stored?


It is speculated that they can be stored for as long as frozen semen - 40,000 years.



> Also, when they fertilise the egg, I assume they do it in a petrie dish and later insert the fertilised egg in the mare - much the same as they would with a human... Is this correct? If not, how do they do it?


No. Invitro fertilization is not done in the equine - at least not thesame way it is done with other mammals. If one does harvest a mare's eggs, in order to fertilize the egg, ICSI (Intracytoplasmic Injection) must be used where a single sperm is actually injected directly into the ovum.



> How do people choose a surrogate mare? Is is simply a matter of convenience, or is there a lot more thought involved (ie, mares conformation, size, previous breeding history, temprement etc) (I'm assuming its the second one, but you never know!)


It is preferred that a mare of comparable size is used, that is under the age of ten and older than four, that has had at least one foal and is reproductively sound. Obviously, you want a mare with a known temperament that is good for nuturing the foal, as well as human friendly. 

Hope the above helps!


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## OTTBLover (Jun 23, 2011)

Avalon Equine - Thankyou for taking the time to give such a comprehensive and informative answer!
I learned a lot 

It is certainly more involved than what I imagined!


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## danastark (Jul 17, 2008)

There is a ranch near me that does embryo transfers. They use QH and TB mares.


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## wild horses (Feb 11, 2011)

This is a good thread, im thinking about doing an embryo transfer for one of my mares this breeding season!


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## OTTBLover (Jun 23, 2011)

wild horses said:


> This is a good thread, im thinking about doing an embryo transfer for one of my mares this breeding season!


That leads me into my next question - what are the reasons someone would do an embryo transfer?


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## nrhareiner (Jan 11, 2009)

When I do it with my mares it is b/c I have a buyer for the embryo. Works out well for all involved. They get a better price and I still get to use my mare.


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## SaddleUp158 (Dec 26, 2008)

What is the average cost tied up in this procedure?


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## Indyhorse (Dec 3, 2009)

I know with some breeds at least, it is often done to get more than one foal out of a certain mare in one year. Breed mare, flush embryo, and then breed mare again nest heat for a pregnancy herself.

I read a study a few years back on a place (I think it was the University of CO) that was using cycling mules (true mollies) as surrogates - fascinating stuff, actually, because although mules are infertile hybrids, they have all the working parts, and can carry, deliver, nurse and raise an implanted foal very well and tend to make VERY good moms.


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## nrhareiner (Jan 11, 2009)

Depends on where you go but on average it is about $4500.


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## bubba13 (Jan 6, 2007)

I was thinking it runs around $3-3500 here, including the use of the recipient mare (but of course not the stud fee).


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## Eolith (Sep 30, 2007)

This is an interesting topic to learn about. So there are various equine reproductive centers that perform this service?


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## bubba13 (Jan 6, 2007)

Yes, but for example, my vet is just a local vet who happens to love doing reproductive work, and she keeps her own herd of recipient mares (mostly show flunk-outs that clients have given her for free).


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## DejaVu (Jul 6, 2011)

One of the reasons for doing embryo transfers, is- say you have Multiple World Champion mare-you, or someone is willing to pay, to own one of her offspring. But you want her to be able to keep showing, and keep her current body condition.. 
Soooo. That's where an embryo transfer can come in. So the biological mare can keep doing whatever it is she's doing, and still be spreading her offspring.

I know someone who did this with her mare. For the reason, she didn't want to have the long lay off of not being able to show, as she was in her prime and still young, but they really wanted a foal out of her.

There are also some mares who are able to be fertilized, but are unable to carry the foal full term. That way, using a recipient mare, that's capable and more likely of carrying and delivering a foal full term, you still get the biological mares foal.


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