06/14/1994

Stringfellow Helping Provide New Options for Cattle Breeders

AUBURN, Ala. - Advances in reproductive technologies in recent decades, such as embryo transfer (ET) and in vitro fertilization (IVF), have allowed breeders to improve the genetic base of their herds and increase the number of calves they can produce. But are these techniques reliable and can they spread disease?

David Stringfellow, associate professor of pathobiology and coordinator of animal health research for the Alabama Agricultural Experiment Station (AAES) and the College of Veterinary Medicine, is attempting to answer these and other questions about the latest reproductive techniques.

Stringfellow's research focuses on the relationship between ET, IVF, and other breeding techniques and the spread of cattle diseases. For Stringfellow, this research is a perfect blend of his background as veterinarian and scientist. While growing up in rural Carlisle, Penn., Stringfellow became interested in veterinary medicine through his family's hobby of raising hunting dogs. During high school and college, he began working on area farms to gain livestock experience before applying to vet school and his interest expanded to large animals.

"My first job was working for a purebred Jersey breeder," he recalled. That experience exposed him to the importance of safe, effective breeding programs for livestock producers. After graduating from Cornell in 1970, Stringfellow entered a private practice and followed closely the embryo transfer techniques, which were becoming popular at the time.

He later worked for the Pennsylvania Bureau of Animal Industry helping monitor brucellosis and other animal diseases in the state before transferring to USDA's veterinary service's division. Through USDA, Stringfellow had the opportunity to come to Auburn in 1980 to work on a brucellosis study that was evaluating the hazards associated with raising female progeny from brucellosis-infected cattle.

"That project showed that, with specific precautions, there is no hazard of spreading brucellosis through embryos, and it helped to clarify some issues related to brucellosis in livestock," he said.

While working on the project, he also completed a master's degree and Stringfellow became a permanent member of the Auburn faculty in 1983.

A major area of current interest to Stringfellow has been disease transmission via IVF. Unlike ET, IVF involves harvesting unfertilized eggs and fertilizing them in an artificial environment, such as a test tube or culture plate. According to Stringfellow, IVF expands on the use of artificial insemination and ET.

IVF was originally developed to study the events surrounding the time of fertilization. The initial clinical IVF work was done to help humans who were having fertility problems, explained Stringfellow. Many of the techniques used in Stringfellow's laboratory are similar to those used in human labs.

As the technique was refined, researchers recognized IVF's potential for use in commercial agriculture as a way to increase calf production and salvage genetics.

Auburn's IVF research began in 1991 when Stringfellow and other scientists in the College of Veterinary Medicine began to investigate the process.

Initially, the scientists viewed IVF as a way to harvest valuable genetics from a cow that was about to be culled because of injury or illness. It was considered a terminal procedure because the only way to harvest the eggs was to remove the ovaries. However, the AU team can now harvest eggs using an ultrasound probe to locate the eggs and a special needle to draw (aspirate) them from the ovary.

"We can even collect eggs from a cow in the early stages of pregnancy without affecting her pregnancy," noted Stringfellow.

Stringfellow's research has focused on refining the laboratory techniques of IVF for clinical use and also is determining if such diseases as bovine viral diarrhea can be transmitted using the technique. This work will help determine if embryos produced by IVF are more or less likely than embryos produced through traditional ET to harbor infectious diseases.

And the research has resulted in a new service for Alabama cattle breeders. "The Large Animal Clinic at the College of Veterinary Medicine has been offering IVF services to breeders for about a year, and they are now ready to expand that service. Our lab provides support services to the clinicians who are providing the embryo transfer and IVF services," Stringfellow explained. "We think there are producers who will find this service valuable, and we are ready to serve them. It is an ideal example of a research laboratory in the Experiment Station supporting the transfer of technology to producers."

The service, which will require a fee, will help fund the research while helping Alabama producers harvest valuable genetics from cows.

Anyone interested in learning more about the service may contact the College of Veterinary Medicine at (205) 844-4490.

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
Contact Katie Jackson, 334-844-5886 or smithcl@auburn.edu

June 14, 1994