Opportunities for Embryo Genotyping
Genotyping embryos offers opportunity to determine defect status before embryos are implanted in a recipient.
STILLWATER, Okla. (Oct. 9, 2014) — Genetic defects are becoming a prevalent issue in today’s beef industry, and will continue to be as we learn more about genotyping. Kirk Gray, veterinarian with Cross Country Genetics explained the process of genotyping via embryo biopsy to attendees of the 2014 Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium in Stillwater, Okla., Oct. 8-9.
Gray explained that the challenges of genetic defects are to overcome the “rules” within an operation’s breeding program and to salvage affected bloodlines. Identifying defects has gotten easier as technology has improved. Rather than reviewing pedigrees, investigating by talking to breeders or progeny testing, Gray said DNA-testing has made testing quicker and easier. It is possible to genotype embryos to identify carrier females and breed them to non-carrier bulls.
To do so, Gray explained that seven days after breeding, the embryo is collected and has a compact inner cell mass. Viable embryos are identified and moved to the biopsy station at the clinic.
The embryos are rinsed as a group in accordance with American Embryo Transfer Association (AETA) certification. Then they are moved to well-A of a Nunc working plate. Gray said older embryos are the best.
Once they remove the media, the embryos are prepared for the biopsy and loaded into individual petri dishes. Then they are moved to the micromanipulator stage and biopsied. The embryos are manipulated and then frozen similar to conventional transfer. They are then sent for a DNA test. Gray said the goals of embryo biopsies are to biopsy all embryos from a suspect collection, accomplish at least 90% genetic status determination with DNA testing, and maintain an acceptable pregnancy rate with biopsied embryos.
He shared testing results of biopsied embryos since 2009 at Cross Country Genetics. There have been 198 collections and 1,499 embryos analyzed. Only 8.33% have come back as “non-determined” whether the embryo was a carrier or not. There has also been much success in gender determination from biopsied embryos, he added.
Gray spoke during Thursday’s ARSBC session focused on use of genomics for reproductive improvement. For more information, visit the Newsroom at www.appliedreprostrategies.com to view his PowerPoint or listen to his presentation.
Comprehensive coverage of the symposium is available online at www.appliedreprostrategies.com. Compiled by the Angus Journal editorial team, the site is made possible through sponsorship by the Beef Reproduction Task Force.
Editor's Note: This article was written under contract or by staff of the Angus Journal. To request reprint permission and guidelines, contact Shauna Rose Hermel, editor, at 816-383-5270.