Ovum pick up and intracytoplasmatic sperm injection

Recent developments in assisted equine reproduction allow breeding foals from sub- or infertile mares and stallions, as well as recently deceased mares. Oocytes can be harvested from living mares by Ovum Pick Up (OPU), in which the oocytes are aspirated trans-vaginal from the follicles. Post mortem, oocytes can also be obtained by scraping the follicles. After maturation, the oocytes can be fertilized. This can be in vivo, by oocyte transfer in which a mature oocyte is transplanted into the oviduct of an inseminated recipient mare, or in vitro. When conventional in vitro fertilization (IVF) is not successful in the horse, Intracytoplasmatic Sperm Injection (ICSI) is applied. For this reason, the Ovum Pick Up-ICSI technique can be successfully applied when the semen is available in limited amount or it is of poor fertility when used for artificial insemination.

After ICSI, fertilized oocytes can be cultured in vitro to blastocysts, after which they can be transplanted into the uterus of a mare. The blastocysts can also be frozen for cryopreservation.

Advantages of the frozen embryos processed via OPU-ICSI

  • Reduce the number of recipient mares by better planning of the embryo transfer.
  • Creating an embryo bank.
  • Export and import from frozen embryos.
  • Less risk during transport than of living material.
  • The embryo’s can be produced outside the breeding season.
  • Sex determinating of the embryo before cryopreservation.
  • The embryos are always at the most optimal time frozen and thawed.

The collection of the oocytes (OPU) is done by the team of K.I. Hof Ter Leeuwe, always on monday or tuesday.

If you wish to apply a mare for OPU and ICSI, she will be evaluated echographically a few days in advance in order to have an idea of the number of follicles present on the ovaries. A mare is a good candidate for OPU if she does not show any signs of heat and if she have a minimum of 10 follicles larger than 1 cm and smaller than 3 cm diameter. This evaluation can also be done by your own veterinarian.

As horses ar typically seasonal breeders, it follows that in the northern hemisphere the best time of the year for Ovum Pick is outside the breeding season. Mares are usually multifollicular during the transitional period from estrus to anoestrus and vice versa.

If your mare qualifies for OPU, she must be brought in a day in advance, so that she can be prepared for the Ovum Pick Up.

The collected oocytes are then transferred to Avantea in Italy for the ICSI. Professor Galli and his team are a worldwide authorothy in performing ICSI. Thanks to our narrow cooperation with Avantea, we can achieve the highest possible result..

Since we are an European recognized center for embryo production, all donor mares for embryo producution on K.I. Hof Ter Leeuwe needs to be tested with negative results on Equine Infectious Anemia (EIA) and Contagious Equine Metritis (CEM). These tests should be repeated every 90 days during the period of embryo production.

Transfer of the produced ICSI embryos

The produced ICSI embryos can be thawed and transplanted to a recipient mare when desired. It is also possible that you supply a mare yourselves that can serve to carry this embryo.

The pregnancy results we achieve after thawing and transplanting of ICSI embryos are 60% pregnancy on 14 days gestation.

Aspiration oocytes and transport to Avantea
Maturation oocytes and ICSI by Avantea
Freezing of the produced ICSI embryos at Avantea /embryo
Thawing and transfer of the ICSI embryos to a recipient mare
Transfer of ICSI embryos to recipient mare Watch pricelist

What are the average results for OPU and ICSI?


At every step there occurs loss. The results are highly dependent on the age of the donor mare and the breed. In the case of young mares the result will be higher than in older mares (+17 years) as the quality of the oocytes decreases with age. A higher result may also be expected for warmbloods than for arabian thoroughbreds, for example. On average, the result is 1 produced ICSI embryo per OPU session.

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