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A common failure in embryo transfer programs is the selection and preparation of recipients. I am often asked which breed should be selected for receiving embryos. To date there is no evidence that any Bos Taurus (British and European) breed is superior. However, many years ago we found Bos...

Student Quarters for Field Experiments I’ve always been interested in history so I thought it would be interesting to briefly look back at the developments in my field of bovine reproduction and as the saying goes learn from history, so our activities over the past may point out our failures...

Demonstrating the damage caused by poor transfer techniques Frequently I have heard of artificial insemination (AI) technicians claiming higher pregnancy rates when semen is placed in the uterine horns. However, a study (Can. VET. J. 1965) reported that AI technicians frequently deposited semen...

There have been many attempts to improve pregnancy rates by administering progesterone (PG) from injections to vaginal suppositories. Unfortunately, results have been well below expectations but have improved with the advent of controlled intravaginal releasing devices (CIDRs) for synchronizing...

The Achilles heel of the embryo transfer industry is the unpredictability of the final results even when optimum techniques have been utilized by experienced persons. I have often thought we should regularly obtain at least a 90% pregnancy rate when considering number one quality embryos were...

We have all experienced frozen straws containing embryos or semen exploding when exposed to the environment or water in the thermos. Unfortunately, the person thawing is accused of making a mistake, but the fault is due to the technician who froze the embryos not sealing the straw prior to...

I have often speculated after carefully transferring a #1 embryo into a recipient with a known corpus luteum (CL), on the correct date of the estrous cycle, following regular cycles, why do we not achieve pregnancy rates around 90 to 100 per cent?  As we all know that rarely occurs at least when...

The survival of frozen-thawed-transferred embryos depends on several factors, and they are based on a subjective classification of quality expressed as #1, 2 or 3 meaning excellent, good or fair quality. However, classification is not 100% reliable as the grading scores vary among practitioners...

When I was running the CSU embryo transfer laboratory our mission  was in  applying  our research results to see if they worked in  the commercial field. There are many examples where a technique works in the laboratory but does not function efficiently when applied commercially. We had over...

Steel reported that embryos graded # 1 (859) resulted in equal pregnancy rates when they were placed in either lower, middle or upper one third of the horn (73%, 73%, and 74%) respectively next to the CL on the ovary, providing the embryo was deposited past the palpable division of the horns...

We received several calls this summer regarding below average embryo collections and unsatisfactory pregnancy results in recipients. These concerns led to the creation of this month’s newsletter which addresses heat stress and its effects on bovine reproduction. Global warming is a term we are...

Recently a cattle owner contacted me regarding frozen embryo classification. He had some frozen embryos stored, classified as Stage 4 which are embryos developed to the compact morula stage usually observed 6 days after first observed standing heat (estrus ) . He had been informed by several...

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...

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...