When you’re putting a lot of “eggs” in one basket, so to speak, by opting for embryo transfer to produce a foal, you expect the offspring of your dreams. Researchers understand that, and today, they’re closer than ever to safely performing genetic testing on embryos to ensure they meet owner expectations before they’re implanted in the recipient mare.

While scientists have been trying to perform these tests—such as to determine the fetus’ sex—for decades, the biopsy procedure involved is often detrimental fetus. According to Florence Guignot, PhD, of the French National Institute for Agricultural Research only about 20% of equine embryos survive the biopsy procedure.

But Guignot and colleagues recently completed research revealing that a previously developed aspiration technique for embryo biopsies yields accurate genotyping results for sex determination in horse embryos, without serious threat to survival. Guignot presented her results at the 2013 French Equine Research Day, held Feb. 28 in Paris.

“In this (equine) species, in the blastocyst stage (at about six to seven days of embryonic development) … the technique of aspirating trophectoderm cells allows good viability of the embryo, in vitro (in the laboratory) as well as in vivo (in the live horse),” she said.

The trophectoderm is the outer layer of the embryo that eventually develops into the placenta. By aspirating cells from this area only, using microscopic tools and preventing the cells from touching other cells indispensable to development—in particular the inner cell mass that will become the foal itself&md