Multi-breed EPD base simplifies selection

News
Feb 8, 2013
by WLJ
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Both the availability of time and the proficiency to digest increasing volumes of information have evolved into two of ranchers’ greatest challenges—perhaps nowhere more pronounced than in making genetic selection decisions.

Through foresight and cooperation, the Red Angus Association of America (RAAA) and the American Simmental Association (ASA) have partnered to assist producers in their genetic selections by breaking industry barriers for the first true multi-breed expected progeny differences (EPDs).

Starting with the Fall 2012 EPD run, both Simmental and Red Angus EP- Ds are now described using the same language, their EPDs are published on the same multi-breed base and scale for growth and carcass EPDs. For the commercial cattleman, this will greatly simplify their selection process as they will be able to directly compare growth EPDs (BW, WW, YW, Milk) and Carcass EPDs (Marb, YG, CW, REA, Fat) across the two breeds, as well as compare EPDs of registered hybrids and composite seedstock.

“The result of this collaboration is genetic predictions based on the world’s largest multi-breed dataset with over 10 million animal records,” said Larry Keenan, RAAA director of breed improvement, “which provides users of Red Angus and Simmental genetics the industry’s most reliable genetic predictions.”

In 2010, RAAA, who had been running joint genetic evaluation with Canadian Angus for the past decade, pooled their dataset with ASA, which already contained significant volumes of Angus and Red Angus data as well as other breeds.

“The Red Angus and Simmental breeds have given the beef industry something cattlemen and women have been asking for since the advent of genetic evaluation, EPDs that can be compared across breeds,” said Keenan.

How this came to be

The Multi-Breed Technical Advancement Committee (MB TAC), whose purpose is to guide improvements in the multi-breed genetic evaluation, recommended the common EPD base to RAAA and ASA in its Strategic Plan. This committee is populated with Red Angus and Simmental breeders, association breed improvement staff, and some of the leading quantitative and molecular geneticists from academia and the USDA-Meat Animal Research Center.

RAAA and ASA Board of Directors accepted MB TAC’s recommendations and worked together with their Breed Improvement Committees to developing a common EPD base for all traits predicted through the multi-breed genetic evaluation. MB TAC’s ultimate goal is to eventually move all traits to the multi-breed model to be presented on a common EPD base.

What is “base?”

For decades, each breed association has presented their EPDs in their own language or base. Base is no more than a reference point for any trait against which subsequent generations of animals are compared.

While some breeds pick a given year, usually several generations of cattle ago, as their base year, RAAA has historically set the base as the average EPDs of a specific group of high-accuracy sires. Either case is intended to assure that the base population on which future calf crops are to be measured against remains stable.

A breed’s genetic trend for any given trait is reflected by the rate at which its breed average EPD moves away from that of its base population. Typically, any breed’s genetic trend represents the selection pressure breeders have placed on the respective trait over time.

Yes, Red Angus EPDs will look different

Producers will notice some changes to how Red Angus EPDs will look. • The Fall 2012 breed averages, and subsequent runs, for Active Dams, Proven Sires and Non-Parent Bulls and Females will be different from prior runs; • The Fall 2012 EPDs for the top 10 percent of the breed or bottom 10 percent of the breed for growth and carcass traits will be different as compared to previous runs.

But, most importantly, the rank between animals will not change. A power bull based on last spring’s EPD run will be a power bull on the new multi-breed base. Likewise, a carcass bull will still be a carcass bull, and a low birth weight bull will still be a low birth weight bull relative to the rest of the Red Angus breed.

In the table, a proven sire that previously had a 62 YW EPD now has an 83 YW EPD, but he is still only an average yearling weight bull. While he is still the same bull, his 21-lb. increase in YW EPD mirrors RAAA’s 21-lb. increase in the YW EPD base.

These new multi-breed EPDs are favorable for Red Angus, presenting the breed’s genetic predictions in a more positive light. The prior bases used by both Simmental and Red Angus undervalued both breeds’ perceived genetic merit relative to other breeds. Thus, the new multi-breed base doesn’t over exaggerate Red Angus; rather it presents the breed transparently and on a more equal playing field versus other breeds.

Study Percentile Ranks

Ranchers can rely on Red Angus’ EPD percentiles to help them understand the new multi-breed EPDs. This simple, yet powerful tool is presented along with all active animals’ EPDs. The percentile ranking of the old, single-trait EPD values and the new, multibreed base EPD values is the same.

Percentile ranks are an easy reference of how any Red Angus animal ranks compared to respective Red Angus sub-populations (i.e. Sire Summary Sires, Active Dams, Non-Parent Bulls, etc.).

“It’s important to realize that although the multibreed base allows for direct comparisons of Red Angus and Simmental EPDs, the percentile ranks for Red Angus animals will continue to simply compare the genetics of Red Angus animals against other Red Angus,” said Keenan. “Thus, an animal that was in the top 10 percent for growth under the old Red Angus base will still be in the top 10 percent for growth in the new Red Angus multi-breed base.” 

Commitment to success

The Red Angus breed’s success results from its commitment to provide tools to the beef industry that ensure the sustained profitability of the ranch families who are Red Angus’ primary customer.

Describing Red Angus and Simmental seedstock on the same multi-breed EPD base will provide commercial customers with the industry’s most reliable and userfriendly genetic selection tools, further ensuring the success of the its stakeholders. — WLJ


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