The researchers wanted to find out how long it takes for horse embryos to travel through the oviduct, if they grow bigger before this journey, and at what stage of development they are during this time. They collected embryos every 2 hours from 120 to 168 hours after ovulation. They discovered that embryos travel through the oviduct between 130 to 142 hours after ovulation. The size of the embryos did not change before or during this journey. Most embryos during this time were compact morulae, with a few being blastocysts.