Successful vitrification of equine embryos >300 microns without puncture or aspiration.
Authors: Kovacsy Sofia, Ismer Ann, Funes Javier, Hoogewijs Maarten, Wilsher Sandra
Journal: Equine veterinary journal
Summary
# Editorial Summary Conventional equine embryo vitrification requires mechanical puncture of larger embryos to prevent ice crystal formation, a labour-intensive step that has limited wider adoption of the technology in breeding programmes. Kovacsy and colleagues developed and tested a simplified vitrification protocol using a human embryo kit adapted for equine use, extending the equilibration phase to 15 minutes whilst reducing exposure to the final cryoprotectant solution to under 90 seconds, eliminating the need for pre-puncture in embryos up to 480 micrometres. Pregnancy rates were comparable between small embryos (≤300 µm; 81.8%) and moderately sized embryos (>300–500 µm; 80%), though the protocol failed in larger embryos (>500 µm), with the largest viable embryo reaching 480 µm. The authors propose that prolonged equilibration allows more gradual cryoprotectant penetration, reducing osmotic stress without requiring mechanical intervention. Whilst the sample size is modest and limited follow-through data constrain confidence in clinical outcomes, these findings suggest practitioners could streamline embryo handling protocols and potentially expand vitrification access to breeding operations where puncture-based methods are impractical.
Read the full abstract on PubMed
Practical Takeaways
- •A non-invasive vitrification protocol can now be used for equine embryos up to 480 μm, eliminating the need for puncture and simplifying the procedure for practitioners
- •This technique maintains high pregnancy rates (80-82%) for mid-range embryos, potentially enabling broader adoption of vitrification in equine breeding programs
- •Embryos >500 μm remain unsuitable for this protocol; current best practice for larger embryos should continue to be used
Key Findings
- •Equine embryos ≤480 μm can be successfully vitrified without puncture pre-treatment using extended equilibration solution exposure
- •Pregnancy rates were 81.8% for embryos ≤300 μm and 80% for embryos 300-500 μm
- •Embryos >500 μm showed 0% pregnancy rate (0/7) with this protocol
- •The largest surviving embryo was 480 μm, demonstrating successful vitrification without mechanical disruption