OPU (Ovum Pick-Up) & ICSI (Intracytoplasmic Sperm Injection)

Ovum pick-up (OPU) consists in the collection of the mare’s eggs (oocytes) directly from her ovary. The OPU procedure is performed on the standing mare after sedation and administration of an epidural anaesthesia.

These oocytes are then transported to a specialised lab within 24h, where they will mature and carry out ICSI.

Although it is an invasive procedure, the rate of complications is very low.

Intracytoplasmatic Sperm Injection (ICSI) is the technique used for fertilization of the oocytes with a single sperm cell, where the latest is injected into the oocyte. After this procedure the embryo goes to an incubator to mature for 7 to 9 days. The obtained embryos are then frozen and stored in liquid nitrogen until transfer into a recipient mare.

Advantages:

• It can be performed any stage of the reproductive cycle and therefore at any time of the year.
• Ideal to obtain an embryo from a subfertile mare or a mare that is unable to carry a pregnancy to term.
• There is no interruption of the sport career of the donor mare.
• Embryos can be stored in liquid nitrogen indefinitely and therefore be transferred when suitable recipients become available (no synchronization needed) and it Is possible to choose the desirable time for the foal to be born.
• Ideal for the use of subfertile stallions.
• Since little amount of semen is required for this procedure, stallions with limit semen storage or extremely costly can be used, since a single straw of frozen semen can be used in multiple ICSI sessions.
• Export and import of frozen embryos.

What to expect from OPU / ICSI:

Chances to obtain one or more embryos per OPU-ICSI session are around 55 %. Pregnancy results after transfer of an ICSI embryo are around 70 %.

These results are variable between individuals, with some mares having multiple embryos every OPU session but unfortunately also mares that fail to produce embryos via OPU-ICSI.

Things to Consider

• Enrollment: unfortunately, there is no available laboratory in the UK to perform ICSI, therefore your mare needs to have swabs and bloods taken in order to export her oocytes.
• To increase the recovery rate of oocytes, your veterinary surgeon will need to do transrectal examination to guarantee that there are a minimum of 15 follicles in both ovaries.
• Semen of your desirable stallion must be available at the exporting laboratory.