Assisted reproduction in Estonian sport horses

Horse embryo Credit Elina Tsopp

 If all goes according to plan, Estonia is on the brink of a pioneering achievement in the realm o
f horse breeding. The imminent birth of the first foal, conceived through a meticulously planned process, marks a significant milestone for the country. 

This innovative method (Ovum Pick-Up and Intracytoplasmic Sperm Injection (OPU-ICSI)) involves extracting an ovum (egg) from one mare, using the OPU procedure, and inseminating it using the Intracytoplasmic Sperm Injection (ICSI) technique, where a single sperm is injected directly into the egg. The embryo is then grown in the laboratory and subsequently transferred to another mare.

Ghent University in Belgium and a few private enterprises already provide an in vitro production service for horse embryos. This service has now been introduced at the University of Life Sciences in collaboration with Luunja Stables and Perila Stables, explained the initiative's leader, Elina Tsopp, a junior researcher in breeding and biotechnology at the University.

The mare, impregnated with an ICSI embryo, is located at Luunja Stables. The embryo transfer was carried out by veterinarian Ulrika Tuppits. “Trials were conducted simultaneously in both stables. The fact that pregnancy was first achieved at Luunja Stable was simply a matter of luck."

 

The trials began two years ago, and according to Tsopp, the easiest way to explain the procedure is that it is very complicated. 

 

"The ovum needs to be injected with one sperm, that is, a single spermatozoon," explained Tsopp. Considering the size of the cells this in itself is already a delicate procedure. But this still does not guarantee the successful fertilization of the ovum. Everything depends on the quality of the cells collected with the OPU procedure, the transport conditions, the quality of the sperm and several other factors, said Tsopp.

The OPU-ICSI technique is in high demand among horse breeders. “Such biotechnology helps to produce offspring from mares involved in top-level sports without disrupting their athletic careers. Furthermore, the OPU-ICSI technique allows obtaining offspring from mares 

that otherwise could not produce offspring or to use the sperm of very valuable stallions more efficiently," explained Tsopp. It's no secret that in equestrian circles, in vitro fertilization is a very hot topic. Nowadays, in addition to selling horses and foals, embryos are also being sold.

Their athletic careers may not give sport horse mares the opportunity for a traditional pregnancy, yet all stables still want to have offspring from the best horses. Now, in addition to embryo transfer, there is also the possibility of obtaining offspring from the best mares through the OPU-ICSI technique: during a quick procedure, oocytes are retrieved from the ovaries, and the horse can go straight back to sport after a rest day. The embryos are taken to the laboratory for fertilization, and the fertilized cells grow in the incubator for 7-10 days until they are ready for transplantation or freezing.

Another significant reason for using biotechnology is the high cost of semen from top stallions. A straw of semen from some stallions can cost 30,000 euros or more. Artificial insemination of a mare often requires two or three straws, and a successful pregnancy is not guaranteed. However, by using the ICSI technique, it is possible to fertilize hundreds of eggs in laboratory conditions with a single straw of semen, providing the best genetic combinations for hundreds of offspring.

Up to 20 eggs can be obtained from one mare at a time using the OPU method, which involves aspirating follicles with a long needle and a vacuum pump. The breeding season for horses falls between spring and autumn, but the OPU method allows for the retrieval of eggs throughout the winter as well. 

 

The first test tube foal in Estonia is due to be born in August 2024.