Genetic Toolbox: Part 2

By: John Maday

The earliest genomic tests for cattle did not live up to expectations, but the technology has progressed dramatically, providing cost-effective tools for accelerating genetic progress in beef herds.

A recent webinar from NCBA’s Producer Education program outlined how cow-calf producers can take steps to accelerate genetic improvement in their cattle and position their herds for future profitability and sustainability.

The webinar featured Kansas State University Cow-Calf Extension Specialist Bob Weaber, PhD, who also serves as faculty coordinator of the K-State’s Purebred Unit, and University of Missouri animal scientist and Beef Genetics Extension Specialist Jared Decker, PhD. This article focuses on Dr. Decker’s presentation on the role of heterosis. Part 1 of the series summarized Dr. Weaber’s presentation on the value of crossbreeding in commercial cow-calf operations.

Decker refers to the “Hype Cycle” (see graph) to show how genomic testing, possibly over-sold in the early days, has gained power and legitimacy as the technology improves.

From the late 1970s to the early 1990s, Decker says researchers were engaged in developing DNA technologies, sequencing genes and identifying markers. With the technology available at the time, it took a long time, and great expense, to generate a small amount of data. In 1990, Decker says, it cost about $5,000 to sequence 1 million base gene pairs. Nevertheless, companies began marketing genetic tests to the industry based on just a small number of markers for a small number of traits. Those early tests, Decker says, did not reflect biology and most later failed validation.

New sequencing technologies reduced the price of sequencing 1 million base pairs to around $600 by 2006, and to $4 by 2009. Today it costs researchers less than $0.50 to sequence 1 million base pairs, allowing collection of vast amounts of data on large populations of cattle, and development of much more comprehensive and accurate tests. Using these tools, Decker says researchers now have moved away from gene testing, instead focusing on genomic predictions using all 20,000 genes in the cattle genome, with ongoing validation a critical component of genomic testing.

Much of the application of genomic technology has focused on testing bulls at the seedstock level. Because each bull produces multiple calves every year, they represent a key opportunity for genetic improvement, particularly in operations that retain heifers for breeding. Decker says the use of genomically enhanced EPDs, and particularly the use of targeted selection indexes that incorporate genomic information, can accelerate genetic progress.


Courtesy : Jared Decker, University of Missouri

Genomic testing enhances the accuracy of EPDs, particularly in young animals and with EPDs for traits that are difficult to measure or those that do not become apparent until later in life, such as cow fertility or longevity. Depending on the trait, genomic testing in a young animal can provide EPD accuracy equivalent to data from 10 to 20 of the animal’s progeny.

In addition to bulls, today’s producers can use genomic testing as a cost-effective tool to aid in selection of replacement heifers. Decker outline several tests available for cost-effective genomic-based selection in replacement heifers.

·         GeneMax Focus This test from Zoetis, Angus Genetics Inc. and Certified Angus Beef, for cattle with at least 75 percent Angus influence, provides a 1 to 99 ranking for average daily gain and marbling for a cost of $17 per head.

·         GeneMax Advantage – This Angus test combines 17 traits into three indexes; Cow Advantage for maternal traits, Carcass Advantage for carcass traits and Total advantage which combines the two for $39 per head.

·         Gelbvieh Maternal Edge Female Profile is a gnomic profile for commercial heifers with high percentage of Gelbvieh influence. It provides a 1 to 10 score for calving ease, maternal calving ease, weaning weight, Yield Grade, marbling and carcass weight for a cost of $26.

·         Red Angus Herd Navigator provides a 99 to 1 score for all EPDs and indexes published by Red Angus Association for $25 per head.

·         Igenity Profiles from Gene Seek provide tests for females in multi-breed crosses. The Igenity Gold Profile includes seven 7 maternal traits, three performance traits and four carcass traits for $40. The Igenity Silver profile provides scores for calving ease maternal, stayability, residual feed intake, average daily gain, tenderness and marbling for $25.

Genomics case study

Decker outlined a case study from the beef herd at the University’s Thompson Research Center, showing how managers generated rapid genetic improvement by using genomic scores to sort heifers.

The study focused on incorporating a genomics-based index into replacement-heifer selection at the center. Beginning in 2014, researchers used the GeneMax Advantage tests from Zoetis, Angus Genetics Inc. and Certified Angus Beef to evaluate the genomic merit of the center’s heifer calves.

The GeneMax Advantage test provides three numeric ratings:

·         The GMX Feeder Advantage index evaluates the contribution to post-weaning performance of future progeny through the feedyard and to the rail.

·         The GMX Cow Advantage index evaluates the maternal value from conception to weaned calf.

·         The GMX Total Advantage index combines those scores for a system-level evaluation of total genetic contribution from conception to CAB carcass value.

The group tested 80 heifers. GMX Cow Advantage scores ranged from 36 to 91, on a 1 to 100 scale, and averaged 71.5. GMX Feeder advantage scores ranged from 34 to 91, and averaged 68.3. GMX Total Advantage scores ranged from 43 to 96 and averaged 77.8.

Using the GMX Total Advantage scores as a selection tool, the researchers selected the top 60 percent of the group to retain for breeding. That shifted the range to a minimum of 79 and maximum of 96, with an average score of 86.2.

Decker calculates that the improvement in genetic merit over one year of selection has added $12.56 more profit per heifer calf and $63 more profit over each heifer’s lifetime. And that is just the first year. Decker adds that genetic improvement accumulates over time, as the female progeny of those replacement heifers and subsequent generations continue to improve. 

Decker refers producers to eBEEF.org, a Web resource for information on genetics on beef production including a range of research articles, fact sheets, FAQ and more.

The full webinar is available online from NCBA.