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Selection Decisions Committee

Evaluation of Genetics by Environmental Interactions

by Barb Baylor Anderson for Angus Productions Inc.

COLUMBIA, Mo. (June 30, 2010) — Artificial insemination (AI) allows bulls to produce progeny that are theoretically raised in a variety of environments around the world. But even with similar genotypes, not all of those progeny will have the same phenotypic response to a change in environment.

Bill Lamberson, University of Missouri animal science professor with a research focus in livestock genetics, has studied the genotype x environment interaction. He told participants at the Beef Improvement Federation (BIF) "Gateway to Profit" symposium that the classic example comes from research done with cattle from Florida and Montana. Basically, Florida cattle outperformed Montana cattle in Florida, and Montana cattle outperformed Florida cattle in Montana.

"The genotype x environment interaction is found in the relative change in performance expressed," Lamberson says. "We used a reaction norm regression of data from bulls to measure the phenotypic response of a genotype to a change in environment. ... One of the things we looked for was a stability of or constant performance for bulls in multiple environments."

Lamberson and colleagues studied Brazilian Nelore and U.S. Angus bulls to determine if there were differences in reaction norms, and whether enough genetic difference existed to develop an expected progeny difference (EPD). They reviewed the performance of all progeny of the bulls that qualified for the study and the performance of the progeny of specific sires in specific environments. Several criteria were established to screen bulls for the research.

"We looked at the heritabilities of the Angus progeny weights and found enough genetic variation for birth weight, weaning weight and yearling weight that you could probably produce an EPD and make progress in selection," he says. "There were highly significant differences among bulls for birth weight and perhaps an opportunity to estimate genetic merit for the trait."

Lamberson is not completely sure why the differences exist, but notes previous work shows consistency increases with heterosis. Genes may be present that impact robustness. Likewise, other components not studied, such as maternal components, could affect results.

"The best followup to this research might be to look at bulls in specific environments and see what happens with the data," he says. "Low genetic adaptability and high performance environments (for example), might yield different results than what we found in this study."

Lamberson spoke June 30 during the Selection Decisions Committee break-out session at the 2010 BIF symposium. Themed "Gateway to Profit," the 42nd annual research symposium and annual meeting was hosted by BIF June 28-July 1 in Columbia, Mo.

Editor’s Note: This summary was written under contract or by staff of Angus Productions Inc. (API). Through an agreement with the Beef Improvement Federation, we are encouraging reprinting of the articles to those who will adhere to the reprint guidelines available on this site. Please review those guidelines or contact Shauna Rose Hermel, editor, at 816-383-5270. PowerPoints are posted with permission of the presenter and may not be reproduced in whole or in part without the express permission of the presenter.

API's coverage of the event is made possible through collaboration with BIF and sponsorship by BioZyme Inc. through its significant gift to the Angus Foundation. For questions about this site, or to notify us of broken links, click here.

Headquartered in Saint Joseph, Mo., API publishes the Angus Journal, the Angus Beef Bulletin, the Angus Beef Bulletin EXTRA, and the Angus e-List, as well as providing online coverage of events and topics pertinent to cattlemen through the API Virtual Library.

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