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Variability of Pregnancy Rates from Frozen/Thawed/Transferred Embryos The problem of low pregnancy rates following the transfer of previously frozen embryos has significantly decreased over the years, but it still does occur as demonstrated in a recent court case. Usually the transfer...

Unacceptable low pregnancy rates can be due to poor management practices of donors and recipients and not the often expected poor embryo technology.  The most common practices causing stress can be divided into, incorrect condition of donors and recipients, transportation problems, rough...

In this report new ideas on improving the reliability of donor responses are discussed, followed by answers to some of the questions posed last month. When considering where to apply management practices the three main areas should be apportioned as follows,  47% on reproduction, 24% on growth...

I have some facts regarding placing two embryos in one recipient. The first investigation was an experiment and the result was 51% twins born alive,the second and third twinning attempts were for commercial reasons and resulted in 52 and 51% twins born alive.There were 50,62 and 51 cows...

I prefer to allow two full estrous cycles before using a recipient or a donor. For maximum results the uterus appears to need that period of progesterone exposure. If the heat periods are unknown then wait 60 days after calving.

Thank you Terry for recognising the'' typo'' error in my reply to a question. The day before I wrote that note I had  undergone surgery and it probably affected my line of thought. By the way I agree that drugs should be limited as much as possible. In fact as I once reported when we were first...

Yes, fresh embryos graded 1s and2s  achieve a 15% higher pregnancy rate than frozen-thawed embryos. From an international survey carried out last year the average pregnancy rate was 67%.

The CIDR protocol is the most reliable method for synchronisation e. g. insert CIDR plus GnRh ( cystorelin ) on Day 0,remove CIDR plus PG ( cystorelin ) on Day 7. CIDRs can be used successfully used twice but they should be cleaned and placed in the refrigerator after use.We have not observed...

  Calving times are similar for regular breeding or embryo transfer,that is calving can be 15 days before or 15 days after the predicted date.

  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...

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...

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...

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...

I am often asked why elevate the head end of the donor?  Embryos and eggs are in the tip of the uterine horn next to the utero-tubal junction.  In order to wash them out the medium has to completely fill the uterus all the way to the end.  In heifers and young cows the uterus is in the pelvic...

I have been finally persuaded by several of my ex-students to defend the vindictive,untruthful character assassination perpetrated by a T. Morris on this forum. Over 30 years ago Morris visited our Colorado State University embryo research laboratory to obtain information on how to freeze...