Embryo Transfer in Beef Cattle

Heidi McGowen Casey Debow Jennifer Silva

WHAT IT IS….. Embryo Transfer is the process of removing embryos from a superior cow and placing them in a surrogate cow where they develop into a calf.

THE PROCESS The process is similar to artificial insemination, which uses superior sperm to reproduce quality bulls. By combining the 2 processes a quality herd could be produced in a short period of time.

The First Step The first step involves superovulation of the superior cow. A follicle stimulating hormone (FSH) is injected into the cow 40 hours before the cow reaches estrus. The hormone induces production of a large quantity of embryos.

At the Same Time... At the same time, the recipient cows are synchronized. They are injected with leutelase, a hormone that regulates the estrus cycle. This will insure that the cows are synchronized with the donor cows.

ESTRUS CYCLES... It is very important that the estrus cycles be at the same point for a successful transfer to take place. Estrus detection is crucial to the process.

Once the Cows are Synchronized... When the donor cow and recipient cows are synchronized, and the embryos are in the 250 cell stage, the embryos are flushed out of the donor cow.

The Process of Flushing A catheter is inserted through the cervix into the uterus. A saline solution is then used to remove the embryos from the lining of the uterus. As the solution drains out of the cow, it is collected and the embryos are removed.

What Happens to the Donor Cow???? The donor cow is given drugs that would create an abortion, just in case any embryos are left inside of her. She will be ready to donate again during the next cycle. After seven donations she is allowed a ‘normal’ pregnancy.

The Embryos The embryos are then processed. They are taken from the saline solution and examined under a microscope. They can then be frozen for later use, or immediately transferred into a recipient cow.

SPLIT The embryos can also be split, which consists of dividing the embryos into 2 halves. Each half can then be frozen or placed into a cow. Each donor cow would then be capable of producing twice as many embryos than usual.

Implanting The embryos are implanted into the cows using a technique similar to artificial insemination. A tube containing the embryo is inserted into the uterus, then the embryo is pushed out. If all goes well, the embryo will attach to the lining of the uterus and a normal pregnancy will occur.

Benefits Transferring embryos allows ranchers to use inferior cows that would not normally be used for breeding.

Benefits One superior cow could also be able to produce many more superior calves than under normal conditions.