Embryo transfer in Cattle
(ET, Embryo flush)
Embryo transfer in cattle refers to depositing an embryo produced by one cow (donor) into another cow (recipient) to allow the recipient cow to develop, deliver, and raise that calf. The embryos are naturally produced by the donor cow and flushed out and recovered at a specific time after breeding. Once embryos are recovered, they are cleaned and graded (quality and stage of development). These recovered embryos can be directly transferred into a recipient cow or loaded into “straws” and frozen in liquid nitrogen to be transferred at a later date. An alternative to naturally produced embryos is to develop them by in-vitro fertilization (IVF).
-What is an Embryo Transfer?
Embryo transfer is the process of collecting embryos (6-8 day old fertilized eggs) from a valuable donor cow and placing into recipient (surrogate) cows.
-The importance of Embryo Transferring in Cattle.
Embryo flushing and transfer is a way to add desirable genetics into a herd. It is also a way to preserve genetics from a valuable cow in case she dies.
-Things to know about Bovine Embryo Transfer
This procedure is not fail-safe. Some cows respond better than others and produce a large number of high quality, transferrable embryos. Others cows, under the same protocol, will produce a small number of transferrable embryos. There are many variables involved in this procedure. The protocol has to be followed appropriately, the donor cow needs to respond appropriately, the donor cow must be inseminated at the correct times, the semen used must be high quality, and the technician must be able to recover and process the embryos without jeopardizing the viability of the embryos. The average number of recovered transferrable embryos is 8-10 per flush. When transferring embryos into recipient cows, the recipient needs to be at the appropriate stage of her estrus cycle, the embryo must be handled properly, and the person transferring the embryo needs to be able to deposit it at the appropriate location in the uterus without causing damage to the lining of the uterus. The expected pregnancy rates following transfer is about 50%. It is important to select recipient cows carefully. She should be free of disease and proven to be a good mother cow. Working with a veterinarian to select recipient cows will increase the success of an embryo transfer program.
-What are the risks of Embryo Transfer in my cattle?
There are some economical risks associated with embryo transfer. It is a fairly expensive procedure, so if the success is poor, the producer can lose money. However, if it is successful, the producer can make more money than conventional breeding. There are a few health risks. It is possible to damage the uterus or even puncture the wall of the uterus when passing the pipette. This usually happens because the cow is not cooperating and moving too much in the chute.
-Things to remember during the Embryo Transfer process:
1. It is best to select proven cows as recipients. Virgin heifers or problem cows do not make good recipients.
2. Good working facilities and experienced personnel are important for successful ET programs
3. Have realistic expectations.
-Should I consult a vet about this?
It is usually best to have a veterinarian experienced in Embryo Transfer assist in creating protocols. Dr. Fuselier is a board certified cattle reproduction specialist and he would be happy to help you with this procedure.