The researchers found ways to freeze horse embryos successfully using a method called vitrification. Horse embryos have been hard to freeze for a long time, but now there are better techniques available. Embryos larger than 300 µm in size can be preserved well, giving good pregnancy results. The scientists discuss why freezing horse embryos has been tricky and show how vitrification is now a promising method. They share the history of vitrification development and mention new techniques being studied to make embryo freezing easier for vets and breeders.