Increasing Genetic Gain

New technologies in cattle reproduction accelerate rate of genetic gain.

by Troy Smith, field editor

BROOKINGS, S.D. (June 19, 2019) — Cattle breeders have practiced genetic selection for thousands of years and accelerated their progress over time — especially during the last 100 years. But the most dramatic progress has been made in the last 50 years. So said Mark Allan, director of marketing and genomics for Trans Ova Genetics, in a presentation at the 2019 Beef Improvement Federation symposium hosted June 18-21 in Brookings, S.D. Allan said progress will continue, with the application of advanced reproductive technologies.

“The greatest improvement in both dairy and beef cattle has come through artificial insemination (AI), and everything else has built on that,” stated Allan, as he recounted the evolution of modern reproductive technologies.

Mark Allan Incorporating genomics into EPD calculations has increased the accuracy of the genetic selection tools, said Mark Allan, director of marketing for Trans Ova Genetics. It has allowed the prediction of genetic merit in younger animals, which allows shortening of the genetic interval to accelerate genetic gain. [Photo by Julie Mais]

It started with early application of AI in the 1950s and advanced to embryo transfer (ET) in the 1970s. In vitro fertilization (IVF) and cloning were implemented in the 1990s, and gender-selected, or “sexed,” semen in the 2000s.

According to Allan, what has changed most in the last several years is accuracy of selection. That’s important when considering that genetic change is described by the quantitative geneticist’s equation that multiplies genetic diversity by accuracy by selection intensity, and divides the product by generation interval.

The application of genomics in creating genomically enhanced expected progeny difference (EPD) values has increased the accuracy of EPDs as genetic selection tools. It has also allowed for the prediction of genetic merit in much younger animals, for which individual and progeny phenotypic data is limited or unavailable. This has allowed for shortening of genetic interval to accelerate genetic gain.

Allan said coupling genomics with advanced reproductive technologies, including ET, IVF and sexed semen, has advanced rapidly in the dairy industry, but more slowly in beef cattle because of the need to consider a greater number of economically important traits, seasonal breeding and the diversity of production environments and production systems. However, the power of intersecting technologies, as applied to beef cattle breeding, is increasing.

He gave an example of how the dairy industry collects DNA on heifer calves soon after birth, gaining a genomic predictor of future milk production. He foresees the day when genomics facilitate high-accuracy prediction of genetic merit for very young beef heifers, and oocytes are collected from beef heifers at 60 to 100 days of age.

Allan cautioned, however, that genomics alone cannot prove an animal’s genetic worth. There is no less need for phenotypic data collection to develop training populations and build the accuracies of EPDs.

“Collection of quality phenotypic data is still required for input and output traits,” Allan said. “That’s still the number one requirement if we’re to continue making genetic gain.”

The 2019 BIF Annual Convention was hosted by South Dakota State University and the South Dakota Beef Breeds Council June 18-21 at the University Comfort Suites and Convention Center in Bookings. ANGUS MEDIA® provides comprehensive online coverage of the event at www.BIFconference.com. Visit the Newsroom for summaries, proceedings, PowerPoints, video and/or audio of the sessions and the Awards page for announcements and photos of award winners.

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