Over the last 50 years, the evolution of bovine reproductive technology has added powerful tools for improving productivity. According to David Faber, of Trans Ova Genetics, artificial insemination (AI) and embryo transfer (ET) stand out as significant components of the breeder’s biotechnology tool box. Now there are additional tools, such as in vitro fertilization, separated semen and nuclear transfer (cloning).
Speaking during the opening session of the 36th Annual Beef Improvement Federation (BIF) Research Symposium May 25, Faber cited new techniques as reasons to expect even greater improvements to productivity during the next decade.
“The old tools won’t go away, but the new tools will enhance their utilization,” he explained. “Individually, these are powerful tools capable of providing significant improvements. However, the greatest gain will come from the application of combinations of these technologies.”
In vitro fertilization (IVF), where the “egg” is fertilized in the laboratory, has been used to complement an ET program, Faber said. It can be applied to females that fail to produce transferable embryos or possess reproductive abnormalities. IVF also may be applied to juvenile donors, as well as pregnant females.
“IVF also provides opportunities to use relatively low numbers of sperm to produce viable embryos,” Faber said. “This allows for the utilization of high-value semen and may provide significant opportunities when coupled with gender-separated semen.”
Faber said application of AI with separated, or sexed, semen has potential for revolutionizing breeding strategies for the beef and dairy industries by enabling breeders to pre-select the gender of calves and target specific markets or needs. However, costs associated with separating semen may have inhibited widespread use for AI. Some challenges also exist for application to super-stimulated donors, making sexed semen less attractive for use in commercial ET programs.
According to Faber, coupling sexed semen with IVF may be the more logical of first commercial applications. The inherent cost of separating sperm fits well into IVF schemes where small quantities of sperm are needed to achieve fertilization.
Presently, Faber said, cloning applications are limited to high-value biomedical or seedstock production. In the future, however, this technology could play a role in commercial beef production. Through cloning, the number of cows required to produce replacement females could be reduced. The same advantage could be captured through use of sexed semen or embryos.
Faber admitted that cloning is not ready for prime time, citing a need for improved efficiency. And while the creation of large numbers of identical individuals has the potential to significantly increase accuracy of genetic selection, the cloning of animals must overcome the scrutiny of society.
