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Genetic specialist explains the importance of aligning trait emphasis with market endpoints

by Wyoming Livestock Roundup

Matching genetic traits between cows and bulls for optimum calf performance is important in any operation. Genetics can play a significant role in how well annaul calf crops perform. 

“There are two steps when matching traits throughout a herd,” says Dr. Bob Weaber, a Kansas State University (KSU) cattle breeding and genetic specialist.  

Weaber states there are two steps to choosing traits. Step one is determining the breeding objective and picking the right breed. Step two is choosing the best individual to fit the operation’s needs in the breed based on expected progeny differences (EPDs), genetic testing and selection indexes. 

Breeding objective 

Producers should be working towards an objective when running a cow/calf operation, whether selling feedlot calves or raising replacement heifers. 

Weaber notes, “It is always good to write down breeding objectives. I prefer to write them down with mathematics rather than just words.” 

He provides the example, “Our objective is to breed cattle which breed as yearlings, calve unassisted and rear a good calf for sale at weaning. We aim to breed functional, easy-fleshing cattle that can forage on the hills over winter, but must have the temperament and soundness to be farmed intensively during calving and the breeding season.” 

“This example covers most of the basics,” Weaber adds. “However, it does not say how operations will be replacing cattle. If producers are raising replacement heifers, there is a different objective than if buying replacement heifers.” 


The bull selection process doesn’t need to be complicated. 

“The strategy I like to use is breeding environmentally friendly cows to market endpoint bulls,” Weaber explains. “Sometimes producers make the selection process too complicated.” 

Additionally, he adds, producers have a tendency to place pressure on trait emphasis while throwing breeding objectives out the window.  

EPDs are the tools used to explain the genetic difference between individual bulls, shared Weaber.  

“Breeding efficiency has to be viewed from an operation standpoint and not on a per cow basis,” Weaber says. “As producers, we should be asking ourselves if it is more beneficial to change the environment to fit our cows or to make our cows more adaptable to our production environment.” 

Economically relevant traits 

Economically relevant traits (ERT) are traits which have a direct cost or return associated with market endpoints. Traits associated with ERTs are indicator traits. 

Weaber explains calving ease would be an ERT. However, birthweight is an indicator trait. Birthweight is also an indicator of weaning weight and yearling weight. 

He shares a good way for producers to tell the difference between an ERT and an indicator trait is to look at how it affects an operation at the market endpoint.  

“If producers sell calves at weaning, weaning weight is going to affect the operation profit,” Weaber shares. 

In this case, weaning weight will be the ERT.  

Reproduction is important because producers need a live calf to sell. 

Weaber recommends producers consider how they run their operation when making breeding decisions. If they sell calves at weaning, producers need to ask how they are replacing cows. If they purchase crossbred replacement heifers, producers should look into a terminal sire who has moderate calving ease and high growth rates. 

However, if producers are raising their own replacement heifers, they should look for bulls who have balance, calving ease, easy fleshing, moderate milk and moderate growth. 

Small producers often have fewer bulls, so those producers need to look for bulls who can meet several traits to match breeding objectives. 

“It can be hard to find a bull who checks off every single box,” Weaber shares. “Producers should keep this in mind because they may need to compromise on some traits. Producers have a lower ability to capture and maintain heterosis when they have a small herd.” 

Maternal versus terminal 

If producers are raising their own replacement heifers, it is important to make breeding decisions centered around a maternal objective. However, if producers are raising calves to go to a feedlot, they should breed towards a terminal objective. 

“Breeding toward a terminal objective results in heavier calves with the benefit of smaller cows, as maintenance requirements are smaller,” Weaber shares. “It leads to increased uniformity throughout the industry due to common breeding objectives.” 

Producers should adjust breeding objectives over the year as operations change and advance.  

Information in this article was presented in the Making Selection Special: Aligning Trait Emphasis with Market Endpoints webinar hosted by Nebraska, Iowa and Missouri Extension services on January 13, 2021. 

Madi Slaymaker is the editor of the Wyoming Livestock Roundup. Send comments on this article to 

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