Tuesday, November 30, 2010
In Death as in Life
This is a picture of two mares carrying fetuses that I ultrasounded last week. Which in and of itself is really no big deal. We do that all the time. The exciting thing about these conceptions is that the stallion has been dead for 13 years, the semen was collected and frozen 15 years ago, the mares have no genetic tie to the pregnancies they are carrying and the pregnancies were conceived in vitro using a fairly high tech procedure referred to as ICSI (Intracytoplasmic Sperm Injection). The procedure involved harvesting unfertilized eggs (oocytes) from the ovary a donor mare. That egg (oocyte) is then placed in special media where it is manually injected with a single sperm cell. The egg then starts dividing, just as it would if it were fertilized naturally. Then after a couple of days of growing in an incubator, the embryo is implanted into an unrelated recipient mare that will care the foal to term and raise it until it is weaned.
The ICSI technique is probably best suited for circumstances where there is a very limited quantity of frozen semen available. Usually, this means the stallion is dead. The beauty of this technique is that multiple pregnancies can be obtained using a single straw of frozen semen. Under normal circumstances, several straw of frozen semen are required to get a single pregnancy. Through the use of this technique it is now possible to establish pregnancies from an extremely limited supply of semen.
The ICSI technique is also useful for situations where, for whatever reason, the mare is no longer producing embryos. This technique bypasses the oviducts and uterus of the donor mare. If the infertility is resulting because of a problem with these structures, this technique takes those problems out of the equation.
It is truly astonishing what is now possible through the use of these advanced reproductive techniques. Congratulations to Jim, Matt and Kathryn Bergren on the anticipated arrival of their foals next year.
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Below is a picture of the famed stallion Ruminaja Ali. He is the sire of the pregnancies discussed in this article. He died in 1997.