The technique of follicular aspiration consists of puncturing the follicular fluid present in the ovaries to obtain oocytes via transvaginal ultrasound. The trained veterinarian after completing the procedure forwards the eggs to the IVF laboratory.
Recovered eggs, normally immature, remain incubated for a specific period for the artificial maturation process.
Intracytoplasmic Sperm Injection (ICSI) is an in vitro fertilization technique used in animal reproduction with the aim of increasing embryo production and obtaining a greater number of animal products with high commercial value or in the case of animals with clinical gestational limitations.
The technique consists of injecting a single sperm inside the egg, and fresh or frozen semen of low quality or high commercial value can be used. Embryos cultured in the laboratory, within approximately 10 days, are evaluated and transferred to a recipient mare or frozen.
What is the advantage of harvesting oocytes from a mare and doing ICSI instead of an embryo transfer?
- Some mares may be unable to reproduce (chronic uterine infections, severe cervical abnormalities, obstructed oviducts, anovulatory follicles, or other medical conditions that prevent the mare from conceiving or provide a healthy environment for the embryo).
- Stallions with low seminal quality, high value animals that died and can be optimized.
- 60-70% of aspirated follicles result in oocytes.
- 50-60% of the oocytes reach maturation and are injected;
- Approximately 20-30% of injected eggs develop into viable blastocysts;
- Pregnancy rate of transferred embryos is around 60%;
- Up to 90 days of gestation, the rate of embryonic loss from ICSI is about 15-20%.
- Results may vary depending on factors related to the mare or stallion, such as:
- age of the mare;
- Seminal quality;
- Breeding season period.
Cryopreservation of Embryos
The technique of freezing embryos by vitrification allows the creation of a genetic bank of high zootechnical value, facilitating the commercialization of genetic material and subsequent transfer at the best time for the female.
Embryo thawing is performed using the devitrification technique, and the survival rate after the process is around 80-90%.
Post-mortem ovarian processing
There is the possibility of obtaining foals via assisted reproduction of mares that died. In this case, the ovaries are collected post-mortem and processed for oocyte retrieval.
Preimplantation genetic testing (PGT)
The Pre-Implantation Genetic Test (PGT) is an analysis that allows identifying genetic alterations in embryos before their transfer. It reduces the risk of transmitting genetic diseases to the offspring, in addition to enabling the sexing of the embryo. The technique is similar to the usual ICSI and is performed on blastocysts between days D7 and D8.