Which are the advantages of the Embryo Transfer as an alternative to the traditional breeding systems?

- To multiply an exceptional mare: It is possible to achieve 3-4 and in some cases up to 10 pregnancies in a season. The possibility of using different stallions in each case allows for comparison of the foals which shall be bred practically together, in order to select the best combination for that mare. - The mare donor of embryos can be empty at the end of the season without need for interruption of its sports activity in order to give birth. - Two-year old mares, not yet with the necessary development can be used as donors of embryos. - Very old, infertile mares due to uterine disease, can be used as donors. The embryo is transferred from the sick uterus to the healthy uterus of a fertile receiver.

Please explain the procedure for the transfer of embryos

Please explain the procedure for the transfer of embryos It is the collection of the embryo from the uterus of a mare with desirable characteristics of high inheritability and its introduction in the uterus of a receiver mare where the gestation and delivery shall take place. The latter shall also breed the foal until it is weaned.

Which are the sanitary requirements that a mare shall have in order to be admitted as donor?

They must be vaccinated against equine encephalomielitis and influenza and to present a negative test of Infectious Anemia no more than 60 days old. It shall also be a docile mare to handle.

How are the services performed on the donor mares?

All the mares are served through artificial insemination with fresh semen obtained by means of an artificial vagina. In some cases, it may be possible to use frozen semen kept at our bank of semen or refrigerated semen sent from the place where the stallion is located.

How do you collect the embryo from the uterus?

This is achieved by means of a flushing of the uterus made with an appropriate liquid medium in order to carry the embryo away. This procedure is innocuous both for the mare and for the embryo. The mare is standing up, in a gangway, with no need of anesthetics or tranquilizers.

When you perform this uterine flushing, do you always obtain embryos?

The 70 % of the uterine flushings made on fertile mares which have been inseminated with semen of fertile stallions result in one or two embryos. When no embryos are obtained, in general, it is because the fertilization has not taken place or the embryo has died before the flushing date.

How do you transfer the embryo to the uterus of the recipient mare?

Once the embryo has been located, it is flushed and loaded on a pistol and transferred in a non-surgical way to the uterus of the recipient mare.

Which is the routine of a donor mare during the transfer program?

When starting the program, the mare is evaluated from the reproductive point of view by means of palpation and echography. Moreover, in certain cases it is possible to perform complementary tests such as a culture of uterine swabs or uterine biopsy. A general physical test is carried out and depending of the health status of the mare when entering the program, it is vaccinated and dewarmed. After the admission test, the mares are put together with the group of donor mares which are kept in field or in mixed pastures or oats. Some mares may be kept in boxes or individual fields depending on the needs or habits of the animal.

Which is the pregnancy rate once the embryo has been transferred?

Around 70 to 80%. The diagnosis of pregnancy is made by means of an echography made a week after the transfer has taken place.

How long must the donor mare remain in the Centre?

This shall depend on the number of pregnancies wished to achieve. In order to produce a pregnancy, around 30 days are enough, but in general the donor mares remain for periods of 3 or 4 months in order to achieve the maximum number of pregnancies possible.

Is it possible to use as donor a mare with a recently born foal?

Yes, but it is convenient to wait 30 days after the foaling in order to start working with it.

Which characteristics must the mare receiver of the embryo have?

We use half-bred mares, 5 to 12 years old, tame and very healthy from the physical and reproductive point of view. If possible, it is better that the mares have given birth before.

How are the recipient mares prepared before receiving an embryo?

They are periodically examined and their reproductive cycles are synchronized with the one of the mare donor of the embryo. Once they have received the embryo they are kept in lots with other mares until obtaining the definitive pregnancy diagnosis.

What is the importance of the recipient mare?

It shall be tame and healthy so that it can raise the foal in the same way. The recipient does not bestow any characteristic on the foal transmitted genetically due to the fact that when the transfer is made the embryo is fully “loaded” with the genetic information of its parents.

How do you report the transfer of embryo and the analysis which guarantee that the born foal is really from the donor mare and not from the receiver one?

The Centre Doña Pilar reports the services and transfers of embryos at the Offices of Genealogical Registers of the Sociedad Rural Argentina. In order to be able to register the product once born, the mare shall be registered as Donor of Embryos and it is necessary to specify the Blood Type of the donor mare and the stallion. Once born, the foal shall be “blood typed” in order to be registered in the Registry of the Breed.

When does the Embryo Transfer season begin?

The mares are admitted from June 1st to 10th if they enter the program of artificial light. In general, these mares start ovulating at the beginning of August. The mares which do not enter until June 10th are admitted after September 15th. The season continues until the month of May.