her specific operation and is something that should be revisited often. Key points within an operation inherently change over time in an adjustment to current markets, available labor, farm transitioning, etc., and the breeding objective must be updated accordingly.
Production Level Considerations Once a suitable breeding objective has been identified, this tool should then help to guide in the determination of what traits directly determine profitability in the outlined setting. “One of the things that is becoming more and more important to recognize is the understanding that maximum trait selection often is probably not our objective if we are a commercial-minded producer. Maximums in biology, the extremes in biology, always come with consequence,” cautioned Weaber. With maximum trait selection taken off the table, the economic-minded producer must then begin to think through what is an acceptable level of lactation, calving ease, mature weight, and other economically relevant traits (ERT) in relation to the amount of feed and labor availability for their specific production setting. It is the answers to the four questions outlined in the breeding objective that lead a producer to which traits directly affect their bottomline or, in other words, which traits are an ERT within their operation and to what level they should select for those traits to maximize profit. “Maximum calving ease, maximum yearling weight, maximum milk, maximum carcass is likely not the optimum solution for anyone. Figuring out the optimum level is what drives profitability,” explained Weaber. “Profit is revenue minus cost. We can make it a lot more complicated than this, but at the end of the day, this is it. What we need to be able to do is connect our ideas relative to revenue and cost streams back to our selection objectives. Practicing selection without understanding-- that is a hobby. If you have enough money that you can select for anything and the outcome doesn’t matter, profitability in cow calf production is probably not the primary focus in your operation. If profitability is really important in your operation, getting your arms around this and making the connection to which traits are important is really critical,” concluded Weaber.
Economically Relevant Trait (ERT) An Economically Relevant Trait is just what it seems. This is a trait that is directly associated with a revenue stream or a cost. “An ERT is a trait that either has a cost directly associated with it, or a revenue stream directly associated with it. The other traits that may have a genetic association or some relationship to our system are called indicator traits,” explained Weaber.
Calving Ease (CE), for example, would be an ERT. Calving ease, or difficulty, has a cost associated with it. A dead calf costs the producer money, while a live calf contributes to the revenue column. On the other hand, Birth Weight (BW) would be an indicator trait. Birth Weight can indicate the ease or difficulty that a calf is born, and it is also positively associated with Weaning Weight (WW), and thus provides an indicator, though an indirect one, of scale weights at weaning time. Both CE and BW are measured and expressed with genetic predictors, or EPDs, and this is where the importance of understanding the difference between an ERT and an indicator trait becomes important. The economically-minded producer should place the most selection pressure on the ERT, while all the while remembering that the importance of those traits will differ based upon the objective and production level considerations. EPDs as a Selection Tool “Ultimately, the phenotype of animals, other than a few traits, do not matter. If you are going to communicate value and try and solve the optimization problem, EPDs and selection indexes provide that,” explained Weaber. Phenotype includes what we see on foot and what is measured, such as actual weights or ultrasound scan data. Reported phenotypes prove important in the calculation of EPDs, but it is important for the contemporary beef producer to not overestimate the importance of phenotype in selection. Phenotypic indicators are a combination of both genetic effects and the environmental effect. The goal of the producer when selecting either herd bulls or replacement females is identifying those animals that have the most potential as parents, or the most genetic potential. In doing so, it is important that all environmental effect is removed, so as to effectively and efficiently compare one animal to its contemporaries. Some examples of environmental effects that would affect phenotypic selectors are age of the animal, age of the animal’s dam, breed composition, feed supplementation, forage resources, sex and more.
Volume 33 • Issue 1 • 2018 l BRAFORD news
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