Skip to Content

The Weekly News Source for Wyoming's Ranchers, Farmers and AgriBusiness Community

Genetic tools provide insight

by Wyoming Livestock Roundup

“The industry is moving forward with superior genetic selection tools,” says Jerry Bohn, National Cattleman’s Beef Association vice president. 

NCBA sponsored a webinar, titled “Moving Forward with Superior Genetic Selection Tools,” explaining how commercial and seedstock producers could utilize genetic tools to improve their herds. 

Speakers ranged from scientists to breed association representatives. The webinar aired Feb. 25 on the association’s “Cattleman to Cattleman” channel on YouTube. 

Progeny expectations

“To be put simply, the expected progeny difference (EPD) tells producers how we can expect one animal to differ from another,” says Mahidu Saatchi, International Genetic Solutions lead genomicist. 

“For example, we could have bull A scored at 10, and bull B scored at zero for yearling weight EPD,” he said. “Bull A will likely produce progeny that are an average of 10 pounds heavier than bull B. This doesn’t mean they will all be heavier but is simply an average.”

Saatchi explained the technology used to calculate EPDs has evolved a lot since its inception. EPDs are calculated using phenotypes, performance and contemporary groups, pedigrees and more recently genetics. 

Advanced EPDs

“We can now use DNA technology like never before,” he said. “We know DNA is the basis of inheritance, and we can use this technology to understand the basic genes that cause differences.” 

He explained despite the complicated nature of DNA technology, running tests is relatively inexpensive to producers and can provide more accurate EPDs. 

“Producers can choose how many data points they want in their reports,” Saatchi said. “The more data points, the more expensive the test will be.” 

“There are two types of single-step models used to calculate EPDs,” Saatchi explained. “The SS-GBLUP uses all markers, adjusts for relationships and assumes all markers have equal impacts. The SS-SHM is a marker effect model that is able to squeeze more information out of DNA by weighing markers based on their impact and leveraging biological facts.” 

He explained, even with the popularity of these tests and models, a very strong computer is required to complete the analyses. Advancing computer sciences have allowed for improvements in the software used to build these models. 

“I have found the BOLT software to be more accurate than the older Cornell system,” he noted. “The need for improving accuracy drives innovation.” 

Seedstock utilization 

“The value of purchasing genomically enhanced, parent-verified bulls is confidence,” said American Hereford Association President Shane Bedwell. 

He explained when it comes to purchasing bulls, verified parentage is extremely important to have accurate EPDs. Advanced DNA technologies used in EPDs has made this process more efficient than ever. 

“When we have better, more accurate EPDs, we can verify young bulls that haven’t performed yet,” he noted. 

“As a whole, we are making a better product from one end of the chain to the other by having genomically enhanced, parent verified animals,” said Bedwell. 

Index selection 

Bedwell explained the index selection was developed in 1943 as a means to simplify sire selection. Ideally, it utilized economically relevant traits to formulate the index and increases commercial line profit.

“To determine economically relevant traits, we have to ask ourselves some questions,” he said. “Ranchers need to determine what their breeding and marketing goals are, what traits directly impact the profitability of their specific enterprise and whether there are environmental constraints.” 

He listed some of the more commonly cited traits including, calving ease direct, weaning weigh direct, yearling weight, mature weight and carcass weight. 

“Some of the indicators for these traits include birthweight, yearling height, mature height and scrotal circumference,” he noted.

“When we utilize the index selection tool, we are simplifying the process of choosing sires,” Bedwell said. “We are able to look at traits weighted based on impact for specific production scenarios.” 

“We have to remember high index values in one trait don’t mean all traits will have high values,” Bedwell said. “A bull could be in the 100th percentile for one trait and the 70th for another, and that’s just how it goes.” 

He also stated, “Breed improvement and advancement of a breed is not always going to match the profit index goals.”

Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to

Back to top