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Thread: Embryo Flushing

  1. #11
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    Dr Metcalf in Australia flushed eggs in dogs over 15 years ago and also froze embryos using those eggs. He did flush eggs from a female that did not conceive anymore bc of age, and fertilized those. All the eggs she had left (memory a bit fuzzy, but I think was many, many - much higher number than released in a normal season). From what I remember from talking to him 12-15 years ago was that the problem was constructing an artificial uterus to grow the embryos. For other animals it was easier than for dogs. He did stop research and went into private practice. He had offers from US universities to come and continue the research, but I think after doing only research for years the terms were not good enough. The status then was that he could take eggs from one female, fertilize with semen and implant into another female. It worked, but only when both females were in exact same stage in their season. So for most practical purposes was not feasible. I remember I asked about transporting the embryos and one could actually implant them into rabbits, ship the rabbit and take out the embryo again when received (-; But did not solve any other problem than transport (plus PETA would not like that one (-: ).

    So the basics have been done long ago, but the resources have not been found to do enough research on how to grow the embryos outside the uterus until the could be frozen in a state where they could be used as with for example cattle. I am no vet and might use some very layman terms recalling these conversations from very long ago.

  2. #12
    Senior Member badbullgator's Avatar
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    Quote Originally Posted by J Gjerpe View Post
    Dr Metcalf in Australia flushed eggs in dogs over 15 years ago and also froze embryos using those eggs. He did flush eggs from a female that did not conceive anymore bc of age, and fertilized those. All the eggs she had left (memory a bit fuzzy, but I think was many, many - much higher number than released in a normal season). From what I remember from talking to him 12-15 years ago was that the problem was constructing an artificial uterus to grow the embryos. For other animals it was easier than for dogs. He did stop research and went into private practice. He had offers from US universities to come and continue the research, but I think after doing only research for years the terms were not good enough. The status then was that he could take eggs from one female, fertilize with semen and implant into another female. It worked, but only when both females were in exact same stage in their season. So for most practical purposes was not feasible. I remember I asked about transporting the embryos and one could actually implant them into rabbits, ship the rabbit and take out the embryo again when received (-; But did not solve any other problem than transport (plus PETA would not like that one (-: ).

    So the basics have been done long ago, but the resources have not been found to do enough research on how to grow the embryos outside the uterus until the could be frozen in a state where they could be used as with for example cattle. I am no vet and might use some very layman terms recalling these conversations from very long ago.
    The problem with this and Bills story lies in the freezing. In Bills case the eggs likely incurred server spindel damage and were never destine to survive. Until just recently the methods used to freeze eggs and embryos was a slow freeze process. Cryoprotectants are introduced to the cytoplasm and then they are slowly frozen to -197 degs. Eggs are 95% cytoplasm and even with the addition of protectants, ice crystals form and cause dammage or death of the eggs. Embryos are more hearty but also have the same ice crystal issues. Recently, in the past five years, a new process of freezing has become common place and is called vitrification. This process also uses diffusion to move protectants into the cytoplasm, but rather than slowly freezing they are "rapidly cooled" to -197 degs. Note the lack of the word frozen because frozen implies ice crystals. Vitrification has a heat exchange of anywhere from -2000 deg/sec to -20,000 degs/sec depending on the carrier used and does not allow ice crystal formation. In human embryology freezing eggs using the slow method resulted in a recovery of 30-50% of the eggs. Vitrification yields 90-100% recovery.
    As to "constructing a uterus" to grow them in, well that is a stretch. No need for a uterus just the proper culture media and the proper atmospheric conditions in the incubator. It is a method that works for many species and dogs would be no different.
    The major problem with this is that there is nobody doing the research. Bulls, horses, and humans have high , market value and have the research money to develop the process. While there are dogs that sell for some jack, it is too easy to produce offspring through much less invasive and affordable methods.
    Anyone have a cool half a million or so laying around? I bet you in a year I could work out the process and culture media and be putting out embryos and offspring. Between the murinae, bovine, and human models a lot of the ground work is readily avaliable. Seriously, any of the vets out there that wants to move on this....?
    Note I am a human embryologist and have worked with bovine, mice, and human embryology but not in any dogs in any reproductive ways other than the good old fashion way.
    Views and opinions expressed herein by Badbullgator do not necessarily represent the policies or position of RTF. RTF and all of it's subsidiaries can not be held liable for the off centered humor and politically incorrect comments of the author.
    Corey Burke

  3. #13
    Senior Member Trifecta's Avatar
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    Ok, I have to chime in here.

    I work at AU's Small Animal Theriogenology Service.

    Embryo transfer in the bitch is not commercially available at this time, either with frozen embroys or as fresh transfers. There are a few key differences that you should be aware about from a species level, as correct, we commonly perform equine and bovine ET work. In the mare and cow, it is pretty easy to synchronize the estrus cycle such that when I flush a 6.5d embryo out of a mare, I can put it back into a recipient mare that is +/-1 day of the donor's cycle. In the bitch, this is a huge problem as we still can't reliably synchronize their cycle (hence, why people have tried freezing the embryos). So, the little embryos aren't always pleased with their new home if everything isn't just right, and its extremely difficult to make it just right. Other things to consider- in the large domestic species, ET work is done non surgically using a catheter passed through the cervix to flush embryos (or in mares, the embryo). In the bitch, this has to be done surgically (for now). There are several people that are working on non-surgial flush options. Frozen or vitrified embryos typically have a poorer survival rate compared to fresh.

    People that currently do this work: the group in s. Korea that does the dog cloning does lots of ET work by default. They recently published a paper on SCNT (cloning) and you can see their pregnancy rates, which were pretty poor typically speaking compared to other species where we do ET. However, pretty freaking amazing when you think about the fact that this ART doesn't really get done in the bitch right now. They were not so kind as to publish their flushing, set up, or recipient protocols. Cute puppy pics though!

    The other person that I know of that may do some of this work is Cheryl Lopate out in Oregon. She is a phenomenal K9 theriogenologist and has done some bitch ET work; however, my understanding is that pregnancy rates are poor and litter size is very small. I have no idea as far as cost, it was just something that she mentioned at the last SFT/ACT meeting in Louisville.

    We have done some embryo work here at Auburn for research purposes but its definitely not something that we offer commercially. However, to the OP, if you're serious about wanting to consider it PM me and I will call you when I get to the office today and I can set up a meeting of the minds here; we have the largest number of board certified theriogenologists for sure in the country and likely the world. I have to go flush some embryos out of a cow this morning
    Natalie Fraser, DVM
    Trifecta Labradors

    Home to my heart dog, Hudson:
    Am/Can Ch. Marshyhope's Satisfaction, CGC, WC, CDX, RE, JH

  4. #14
    Senior Member ks_hunting's Avatar
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    Lots of great responses in this thread... very informative.

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