Linda Benedict | 10/30/2004 1:47:43 AM
Soon the portrait of another farm animal first will hang on the wall of the narrow hallway at the LSU AgCenter’s Embryo Biotechnology Laboratory, located near St. Gabriel, La.
This will be of a big-eyed, lop-eared blonde Brahman named “Gracie,” born this year on Elvis Presley’s birthday, January 8. She is the first clone of a cow to be produced from a new type of freezing procedure for an egg, or oocyte, called vitrification.
“This vitrification procedure adds a new dimension to our embryo research,” said Robert Godke, LSU AgCenter project leader for reproductive physiology research. He started the tradition of hanging pictures of firsts for the laboratory back when the new facility opened in the mid 1980s.
Some of the pictured animals are firsts for the AgCenter, such as the first calves produced by splitting embryos. But others are also firsts for the world, including the first horse born through a test tube fertilization procedure that used oocytes from a pregnant mare in 1998 and the first cloned goats to produce a heart medication in their milk in 1999.
“The oocyte is one of the largest cells of the female’s body and contains a lot of water,” said Sabrina Luster, Godke’s graduate student responsible for the research project that brought Gracie into the world. “When a cell freezes and then thaws, this creates ice crystals that can disrupt the cell membrane, causing a cell to die.”
Because of this, scientists have been somewhat limited in their embryo research to fresh oocytes near at hand. Some female animals, such as goats, produce oocytes only during the fall breeding season. To increase their production, such as in cloned goats that synthesize a pharmaceutical product in their milk, it would be valuable to freeze and store oocytes for future use and also for transporting to other parts of the country for embryo production.
As part of her graduate study, Luster developed a procedure to preserve an oocyte in a super cold gel. This is what vitrification is. It prevents crystals from forming. Through vitrification, the egg can stay intact long enough for cloning.
“Cloning involves removing the female genetic material from an oocyte and replacing it with an adult cell from the animal to be cloned,” Godke said.
Gracie started as a vitrified oocyte after coming to the biotech laboratory from Wisconsin via an overnight mail delivery service. The nuclear material was removed from this oocyte and replaced with a cell taken from a big, beautiful Brahman cow who resides at the LSU AgCenter’s Ben Hur Research Farm, which is about halfway between the campus and the biotechnology laboratory.
Luster used a cow in her research rather than a goat because of the economic importance of cattle production to the state of Louisiana.
Multiple cloned embryos were prepared for nonsurgical transfer to recipient cows. Of three pregnancies, one went to term.
“She looks exactly like the cell donor cow,” Luster said of Gracie, who was born via Caesarean section weighing in at 105 pounds, a normal birth weight for that breed. Because of all the human handling she underwent, her surrogate mother did not accept her to nurse. Luster and fellow animal science graduate student Kyle Hebert became her caregivers.
Luster is scheduled to graduate in December, but Gracie will remain under the watchful eye of LSU AgCenter scientists studying the long-term effects of cloning on cattle.
“There are still unknowns with the animal cloning process,” Godke said. “Some day it could be another tool in assisted reproduction for farm animals. At present, efficiency needs to be improved and it’s still too costly.”
The main reason Gracie’s portrait has not been added yet to the wall of fame is that the 7,000-square-foot lab is being expanded to nearly double in size. Renovations are to be complete by the first of the year.
Linda Foster Benedict
(This article appeared in the summer 2003 issue of Louisiana Agriculture.)