by David Roffey DVM

Some Devon Breeders are using Embryo Transfer (ET) in our breeding programs; some are considering using it and others have heard of it— probably hearing the good, the bad, and in some cases, the very ugly! As a practicing veterinarian starting ET work part time along with my general veterinary practice in upstate New York in the early 1970’s and then doing exclusively Embryo Transfers until the late 80’s, I had many wonderful experiences in this exciting field during its infancy.

The purpose of this article is to help familiarize you with the process by providing a very brief history, a few current ideas and techniques, and expected results of embryo transfer today.

Brief History

The first ET calf was produced experimentally in 1951. Commercial embryo transfer started here in the USA and a few European countries in the very early 1970’s. The first calf produced from a frozen embryo occurred in 1973. By 1980, commercial frozen embryo technology had become economically feasible and thus important to the livestock industry. This, you might remember, was during the exotic Continental breeding frenzy.

Today

Freezing cattle embryos for later implantation has become a very valuable tool. Direct transfer freezing techniques allows the embryo to be thawed and implanted (transferred) without need of a post-thaw microscopic examination or re-hydration of the frozen embryo. This technique has been available for the past 15 or 20 years. It has the look of breeding a cow AI but it does require considerably more skill and experience.

Through approved washing procedures prior to freezing, embryos can be rendered pathogen free. This offers immense security for the buyers of frozen embryos.

Expected Results

The results expected have changed little over the past 20-25 years, but in techniques used now make it so much easier to implant under farm conditions.

Years ago in the early 70’s was when I started Ovatrans International Corporation, both the embryo recovery from the donors and the implantation into the recipients was done surgically. The cost for these early pregnancies were several thousands dollars each.

The percentages of pregnancy rate in the mid 1970’s were comparable to todays. Surgical implantations were actually slightly higher than today’s non-surgical transfers. The quantity and quality of embryos harvested per donor remain nearly the same.

Today, transfer of fresh grade 1 and 2 embryos into well-managed recipients should range from 65 to 75% pregnancy rate at ninety days. Frozen grade 1 and 2 embryos with direct thaw and transfer techniques in the same well-managed recipients should range from 50 to 60% pregnancy rate at ninety days.

Donors generally produce on average 6-8 transferable embryos per flush. Virgin heifers will on average produce fewer embryos than adult cows. Older cows also can be expected to produce less than middle-aged cattle. Generally, one out of four donors will not produce any viable embryos for a variety of reasons. Conversely, twenty or more transferable embryos are not uncommon from a single donor.

Many factors in the embryo transfer process are critical. If you have any weak links in the proverbial chain— disasters can and most likely will occur at that link!

Obviously, management, management, and management are key! The donors, the recipients, heat detection, semen quality, AI sired or natural service, timing and the skill of the personnel involved are all important factors in the actual ET process. Any one of these factors can ruin the whole. My advice – If you don’t have someone already performing to these industry standards, seek out a Certified AETA person.

The American Embryo Transfer Association

AETA Logo

The American Embryo Transfer Association offers a Certification Program, which is approved by the USDA/APHIS. Working together in cooperation, quality standards and protocols for exportation of frozen embryos to foreign markets have been formulated. This also insures the highest quality and credible performance results for US clients.

The AETA Certification Program was established in 1985. All certified Embryo Transfer Businesses must have either a licensed Doctor of Veterinary Medicine or a PhD in animal reproductive physiology operating the Embryo Transfer Business. These individuals are then Certified after a thorough examination process of personnel, equipment and facilities.

Now, you may ask, cannot someone who is not Certified be as competent as those who are officially Certified? Of course! But do you know who they are? Sometimes using an unproven entity can be very expensive and very disappointing! At least with the Certification you know with whom and what you are working. Their peers have already scrutinized them!

Rewards

Please don’t misunderstand what I’m saying! ET can be very rewarding and the results very predictable, BUT leave nothing to chance. Employ the best, most experienced people available. The most important link in this process, in my opinion, is the embryo transfer company you chose. By the way, I no longer do ET work other than some of my own cattle and I have a Certified Company freeze my Devon embryos. You can feel confident, if you choose an organization that is AETA Certified, that you are getting experienced and competent ET practitioners. There are approximately 140 Certified Companies in the US. Certified Companies will use this logo. For listings of its members and more information go to www.aeta.org.

Many of us know or have heard the horror stories concerning embryo transfer. It has been a problem of the recent past in the Devon breed. This is not the norm when dealing with reputable firms.

If you are thinking of using ET in your herd, contact those you are considering employing several months (3-4) ahead of the anticipated flush date. Listen to their advice and seek several experienced sources if need be.

If you are purchasing frozen embryos, ask the seller for a guarantee. The guarantee will likely be based upon some required pre-conditions to which you will need to meet; however, in the long run, these will benefit your results.

Why consider Embryo Transfer in your Devon Cattle?

  1. Due to the price of and availability of Devon females, ET warrants consideration.
  1. If you are considering using some scarce or rare semen, you could get more offspring per ampoule or straw of semen.
  1. More rapidly multiply the higher quality cattle in your herd.