"With the continued changes in the equine industry, particularly the reproductive industry, we need to have a reasonable embryo recovery rate," said Jason J. Hudson, DVM, veterinary resident at Colorado State University (CSU). "With multiple foals able to be registered per year, along with superovulation in the mare and advances in cryopreservation of equine embryos, we need to have the ability to have enhanced embryo recovery rates."

Hudson found that embryo recovery can be enhanced by slight modifications of the standard embryo flush technique, and embryo transfer success can be improved by verifying that the embryo was not retained in the tip of the sheath with which the veterinarian performs the embryo transfer.

 In the commercial embryo transfer program at CSU, veterinarians attempted to recover 334 embryos in 2002-2004. A standard flush of three infusions using 4 liters of media yielded a 35% success rate in recovering embryos. After instituting an extra flush, 46 more embryos were recovered (14%). The overall recovery rate was 49% (163/334).

In a recent study performed at CSU where Hudson modified the flush technique (see the following description), 73 flushes were performed after 255 ovulations (these mares were superovulating due to equine follicle stimulating hormone provided by Bioniche). Hudson said 148 embryos were recovered (107 embryos were recovered after the standard flush and 41 were recovered after the "extra" flush), which worked out to a 58% embryo recovery rate