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Offline ETschool.com

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Embryo Transfer - Frequently asked Questions and Answers
« on: April 06, 2013, 07:35:20 AM »
In this post I am including several frequently asked questions we get regarding embryo transfer. Please contact us with any questions.

Question:  
Since graded embryos are transferred by trained technicians, using prepared recipients why do we not always achieve optimum pregnancy rates?
Answer:
In   trouble shooting requests for help around the embryo transfer industry often the condition of the donor or even more frequently the recipients is the problem while the embryo transfer techniques are up to accepted standards. On the other hand there will be periods of frustration when nothing seems to work and one should remember we are attempting to apply 21st Century techniques to a species developed 50,000 years ago.

Question:
Why do donors and recipients have to be in the right condition?
Answer:
Donors are often too fat for optimum responses to our synchronizing and superovulation drugs while this condition is regarded as the choice form for show purposes. This type of donor frequently demonstrates signs of estrous behavior but do not stand, then 7 days later cystic follicles are palpated instead of the desired corpora lutea (CLs).When recipients are overweight the incidence of ovulation decreases so 7 days after heat lutein follicles are found instead of the expected CLs. I have rejected up to 50% of a group of prepared recipients due to this problem. In addition the reproductive tract in fat donors and recipients is more difficult to palpate which may lead to inefficient flushing and accurate placement of the transferred embryo in the recipient, when even identification of a CL may be difficult in fact on examination of the reason for low pregnancy rates in recipients common problems have been incorrect identification of a CL and the embryo placed in the wrong horn. A spinal block is of significant help when transferring embryos. This discussion of CLs leads to another area where again significant costs are imposed on recipient owners.

Question:
Why do some embryo transfer technicians cull so many recipients?
Answer:
I have observed recipients rejected because the CLs were considered too small, the wrong shape, or fluid was palpated in the CL. In the early days of embryo transfer embryos were transferred surgically under a general anesthetic after rectal palpation for a CL so we took the opportunity to measure the CLs and comment on their shape and size when the tract was exposed. We found no differences in these described CLs. A CL was called cystic when fluid was observed or palpated which is an unfortunate term because this type of CL is a normal phenomenon and cystic denotes a pathological condition. Our data confirms this statement with no reduction in pregnancies following embryo transfer. Relatively recently this type of CL has been designated a CL with fluid. With the significant increased costs of drugs, feed and labor unnecessary culling of recipients is costly.

Question:
Why do we too frequently miss observing standing heat?
Answer:
Observation and recording of standing estrus can be another area of inefficiency leading to increased costs. Removal of a calf after the last prostaglandin (e.g. lutalyse) injection will improve the incidence of standing heat. The calf can be returned to the mother as soon as standing heat is observed. Repeated suckling causes increased release of a hormone called cortisone which negatively affects the reproductive hormones. We have found a thin line of pressure pack paint ( incandescent orange or fire engine red are the best colors ) on the tailhead has proved a very efficient and reliable method of detecting standing heat, particularly useful in hot humid weather when standing heat increases at night. Incidentally many owners consider a natural heat increases the chance of a pregnancy compared to an induced synchronized heat, however our data has shown there is no difference providing a CL is present.
 
Question:
Should we use a failed recipient a second time?
Answer:
Yes, at least one more time assuming the embryos are graded 1 or 2. In one of our early experiments we implanted grade 1 or 2 embryos into crossbred beef heifers, those that failed to establish pregnancies over 3 attempts we asked the question ,did they fail because they are sterile or were they not capable of establishing a pregnancy with a transferred embryo. To clarify this question we artificially inseminated this group and after 3 attempts 88% were pregnant. So the very occasional recipient will fail due to rejection of the implanted embryo. However after one transfer a failure may be due to the embryo or due to the technician. In addition approximately $100 has been added to the cost of the recipient due to probable hand feeding, heat detection and estrus synchronization, so try her once more.

Question:
Why do some donors fail to establish regular estrous cycles after flushing?
Answer:
Occasionally donors are not observed for heat after collection and do not establish regular estrous cycles. After 3 superovulations some donors will produce ovarian cysts. The most common one is a lutein cyst and in this case the donor will not demonstrate heat. Early treatment is usually successful following an injection of a PG. In other cases the donor is in constant heat indicating a follicular cyst. Treatment in this situation is manual per rectal rupture plus an injection of GnRh (e.g. cystorelin).

Question:
A common question is should we superovulate heifers?
Answer:
Once again from our records it is possible to impose this treatment on heifers providing care is observed then future fertility is not affected. Often in the early days too much FSH was administered to the young animals and if they were in the mode to respond then ovaries could grow to the size of a grapefruit, when this occurs the ovaries are heavy  prone to damage and significant hemorrhage leading to upper reproductive adhesions and subsequent infertility. Often the eggs disappear into the abdominal cavity, those that enter the oviducts often are not fertilized and the few embryos produced are of poor quality. However every so often many embryos are produced and these are the ones that become well known. Basically use conservative doses of FSH and make sure the heifer is cycling regularly even before estrous synchrony drugs are administered.

If you pay attention to details and learn from experience embryo transfer can be very rewarding. It has to be a team effort consisting of a good cattle manager and a competent embryo transfer technician.   Good Luck.

Dr. Peter Elsden
The International Embryo Transfer School
Dr. Peter Elsden

Offline BTDT

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #1 on: April 06, 2013, 10:08:55 PM »
Is a cow ever too old to flush? 
Does the donor cow age affect embryo conception?
What fails most: flush technician including freezing, implanting technician, embryo failure, or recep failure? 
What is the minimium number of head should someone do to be "succesfully competent" in doing ET work?


Thanks for the good post.

Offline firesweepranch

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #2 on: April 07, 2013, 08:20:59 AM »
I have a question;
When a recip is seen in standing heat, what is your window of time for putting the embryo in? I know it is 7 days, I am talking hours, so say the recip is standing at 8am, can an embryo be put in at 8pm that day (or day before) and still expect conception? What is the max hours you can go....
God, family, and Simmental cattle;  that's what makes life worth living!

Offline frostback

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #3 on: April 07, 2013, 08:29:44 AM »
I have a question;
When a recip is seen in standing heat, what is your window of time for putting the embryo in? I know it is 7 days, I am talking hours, so say the recip is standing at 8am, can an embryo be put in at 8pm that day (or day before) and still expect conception? What is the max hours you can go....
I am not the expert that wrote this but Ill answere it. Yes you can use a 8 day heat recip. Just tell the tech about it and he will look at the age of the embryos to help make the decision of what egg goes in it. When I was working at a place that did a bunch, you would sort the recips by day of heat, use the 7 day heats first and then the am 8 day, and then the 8 day pm if you still had embryos left. Can use some 6 day pm heats too. Even when doing a small number write down when exactually the recip came in and like I said the tech will look at the age of the embryo to help decide who gets what. This is where a good palpation helps make the decision easier.
Some peoples true character only comes out in PMs.

Offline YoungGunCattle

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #4 on: April 08, 2013, 10:26:37 AM »
What is the difference between flushing and IVF?

Offline frostback

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #5 on: April 08, 2013, 11:23:55 AM »
http://transova.com/ivf.html                            Here is a page on IVF.
http://transova.com/embryo_transfer.html       And one on Flushing.
Some peoples true character only comes out in PMs.

Offline BTDT

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #6 on: April 08, 2013, 12:53:13 PM »
What is the difference between flushing and IVF?

IVF is when the EGGS are flushed from the cow and fertlized in a petri dish by hand, using less semen because you are doing it manually.
Flushing is when the cow is super ovulated and then AI'd. Seven days later the EMBRYOS are flushed, taken out, and then frozen or put in a recep.
Eggs - not fertilized. What a female ovulates
Embryos - a fertilized egg


Offline firesweepranch

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #7 on: April 08, 2013, 02:04:35 PM »
I have a question;
When a recip is seen in standing heat, what is your window of time for putting the embryo in? I know it is 7 days, I am talking hours, so say the recip is standing at 8am, can an embryo be put in at 8pm that day (or day before) and still expect conception? What is the max hours you can go....
I am not the expert that wrote this but Ill answere it. Yes you can use a 8 day heat recip. Just tell the tech about it and he will look at the age of the embryos to help make the decision of what egg goes in it. When I was working at a place that did a bunch, you would sort the recips by day of heat, use the 7 day heats first and then the am 8 day, and then the 8 day pm if you still had embryos left. Can use some 6 day pm heats too. Even when doing a small number write down when exactually the recip came in and like I said the tech will look at the age of the embryo to help decide who gets what. This is where a good palpation helps make the decision easier.
Yes, but you are talking fresh here. I am talking about frozen. We buy a lot of eggs and put them in recips on natural heats. So, we have no clue about the egg other than it is a number 1. I always try to set up our vet that does the embryo work to come out when the cow is exactly 7 days (meaning, if she was in standing heat in the AM, have him out to put the egg in at the same time she was observed in standing heat just 7 days later). I was just wondering what the window of opportunity was - how much does conception drop if you are off by 12 or 24 hours?
God, family, and Simmental cattle;  that's what makes life worth living!

Offline TYD

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #8 on: April 08, 2013, 02:45:45 PM »
Which synch protocol seems to have the best conception rates? Do you seem to see stronger heats on one over another ? Does one drug seem to work better than another

Offline frostback

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #9 on: April 08, 2013, 07:51:32 PM »
I have a question;
When a recip is seen in standing heat, what is your window of time for putting the embryo in? I know it is 7 days, I am talking hours, so say the recip is standing at 8am, can an embryo be put in at 8pm that day (or day before) and still expect conception? What is the max hours you can go....
I am not the expert that wrote this but Ill answere it. Yes you can use a 8 day heat recip. Just tell the tech about it and he will look at the age of the embryos to help make the decision of what egg goes in it. When I was working at a place that did a bunch, you would sort the recips by day of heat, use the 7 day heats first and then the am 8 day, and then the 8 day pm if you still had embryos left. Can use some 6 day pm heats too. Even when doing a small number write down when exactually the recip came in and like I said the tech will look at the age of the embryo to help decide who gets what. This is where a good palpation helps make the decision easier.
Yes, but you are talking fresh here. I am talking about frozen. We buy a lot of eggs and put them in recips on natural heats. So, we have no clue about the egg other than it is a number 1. I always try to set up our vet that does the embryo work to come out when the cow is exactly 7 days (meaning, if she was in standing heat in the AM, have him out to put the egg in at the same time she was observed in standing heat just 7 days later). I was just wondering what the window of opportunity was - how much does conception drop if you are off by 12 or 24 hours?

No you would be fine with frozen too. We do frozen this way all the time. If you know the age of the eggs it just better.
Some peoples true character only comes out in PMs.

Offline CMAHerefords

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #10 on: April 08, 2013, 08:38:59 PM »
Do eggs that are put in 'fresh' have a better conception rate than frozen eggs?

Offline frostback

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #11 on: April 08, 2013, 09:11:03 PM »
Yes.
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Offline ETschool.com

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #12 on: April 13, 2013, 04:48:38 PM »
Is a cow ever too old to flush? 
Does the donor cow age affect embryo conception?
What fails most: flush technician including freezing, implanting technician, embryo failure, or recep failure? 
What is the minimium number of head should someone do to be "succesfully competent" in doing ET work?


Thanks for the good post.

No, cows will produce eggs until they die providing they are still healthy.  We once recovered 18 transferable quality embryos from an 18 year old cow. However older cows as a group will yield fewer embryos. The best years for embryo production are from 3 to 10 years of age. 

Initially freezing techniques were mostly at fault.  However, a frequent problem has been the quality and management of recipients.


« Last Edit: April 14, 2013, 12:15:06 PM by ETschool.com »
Dr. Peter Elsden

Offline ETschool.com

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #13 on: April 14, 2013, 12:19:23 PM »
What is the difference between flushing and IVF?
So called "flushing" involved fertilizing the eggs in the cow and waiting for approximately 7 days and flushing out the embryos from the uterus which are then transferred into recipients.  IVF involves the collection of eggs from the follicles, fertilizing them in the culture dish, culturing them to the stage of morula or blastocysts followed by transfer into recipients.  IVF is a much more intricate technique which cannot be taught in a short course scenario
Dr. Peter Elsden

Offline ETschool.com

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Re: Embryo Transfer - Frequently asked Questions and Answers
« Reply #14 on: April 15, 2013, 05:50:13 PM »
I have a question;
When a recip is seen in standing heat, what is your window of time for putting the embryo in? I know it is 7 days, I am talking hours, so say the recip is standing at 8am, can an embryo be put in at 8pm that day (or day before) and still expect conception? What is the max hours you can go....
  There is a 3 day window for transfering embryos,unlike AI where there is only a few hours e.g. if the donor was flushed  7 days after first observed standing heat  then the embryo can be successfully transferred into a synchronised recipient in standing heat 6,7 or 8 days previously. If the donor and recipient are 1.5 days out of synchrony then the pregnancy rates will be similar to frozen-thawed embryos i.e. 15% lower.
Dr. Peter Elsden

 

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