Jun05

Technology Influencing Beef Cattle Genetic Merit Predications

on June 5th, 2012 at 7:55 am
Posted In: Cattle Breeding, Cattle Breeding, EPDs, Cattle Breeding, Genetics, Cattle Breeding, Genomics

The Beef Improvement Federation (BIF) is an organization founded in 1982 by cattle producers, academia and statisticians set out to advance the science of understanding inheritance factors in beef cattle and developing uniform procedures for predicting genetic merit. BIF recently hosted its 44th Annual Meeting and needless to say, technology has greatly influenced the calculation and development of procedures and guidelines for genetic improvement of beef cattle since the organization was initiated. From the development of EPDs (expected progeny differences) to the early genetic markers to today’s modern genomic-enhanced selection tools, changes are rapidly taking place and impacting the genetic prediction of breeding values yet still focusing on measuring breeding traits that are economically important to commercial beef production.

EPDs were developed as a prediction, based on the available data of what that animal is expected to transmit to its future offspring. EPDs are valuable in making selection decisions (e.g. sire selection) because they are used when comparing two or more animals and the difference between the animals’ EPD predicts the difference in performance of future progeny of that animal for the given trait. The use of EPDs to advance genetic change in the beef cattle industry is common and used extensively across both the seedstock and commercial industry. EPDs can also be used to determine how a bull ranks in the breed compared to the breed average for a given trait. Breed associations publish the breed average and percentile rankings of the traits measured.

The incorporation of new technologies such as DNA or molecular information has further advancing beef cattle selection tools. Early DNA marker information has been beneficial to the beef industry to identify parentage, genetic defects, and coat color. Today, the DNA sources of information represent a rapidly developing new technology which is impacting genetic selection in the beef industry. Commercially available tests allow for the scan of the bovine genome and it’s this information gleaned from the bovine genome that is used in the calculations of EPDs. This technology now allows for genetic predictions to consist of the integration of traditional EPDs with genomic data derived from sampling DNA and evaluating it for gene markers.

In the early stages of genomic development these predictions were originally referred to as Marker-Assisted EPDs (MA-EPDs) and were first published in the American Simmental Association’s Fall 2004 Sire Summary, measuring carcass merit and tenderness traits. Further industry research resulted in the publishing of DNA enhanced EPD predictions for the Angus breed called molecular breeding values (MBV’s) or (GE EPDs). The American Angus Association began including genomic predications into EPD calculations in 2009. The list of traits calculated with traditional EPDs and genomic predictions to create genomic-enhanced EPDs continues to expand for the Angus Association. Additional breed associations are evaluating the use of genomic-enhanced EPDs with anticipation of releases of this information in the near future for some of the traits in their suite of EPDs.

Researchers have found that the use of traditional EPDs and genomic results which are evaluated separately leads to double counting of information and will lessen the efficiency of the information. The new genomic enhanced-EPDs and accuracy account for all sources of information which are available on the animal of interest (e.g. pedigree, own record, weights/measures, and genomic results). Phenotypic measurements, weights and measures such as weaning weights, scan data, etc., are still an important part in the development of EPDs. Genomic results are indicator traits in the evaluation and do not completely describe the variation in the traits of interest therefore the inclusion of them allows the genomic data to become an additional piece of information to aid in the characterization of genetic merit.

Source: Lynn Gordon, South Dakota State University Extension

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