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Simmental Genetic Trends

Are Your Genetic Decisions Taking You in the Right Direction?       |     

By Jackie Atkins, Ph.D., Director of Science and Education Operations          

 

Each April, we set aside time and space in our magazine to look at the genetic trends of the purebred Simmental over the last 20 years. It’s always interesting to take a step back from all the programs, publications, and other projects that occupy most of our days, and simply pause and see if everything we are doing is moving our members’ cattle in the right direction. And by “we,” I mean we. I view the community of the American Simmental Association’s members, their customers, our board of trustees, and the staff at the ASA as a big team pulling in the same direction to improve the genetics available to the commercial beef cattle industry. Of course, the key to change and improvement lies with you, our members. We can provide tools, genetic predictions, and education about ways to improve genetics, ut ultimately the members hold the power of the final decision. If the programs aren’t a fit, they won’t be used. If the genetic predictions don’t align with what the membership thinks will be successful, they won’t be used. Ultimately, the commercial relevance of our members’ cattle is the highest priority for the ASA team, and decisions made to increase the commercial demand for our members’ customers are at the heart of all the projects and programs happening at the ASA. In order to make sure we are all pulling in the right direction, here are the genetic trends of the purebred Simmental population over the last 20 years.

Before we dive into the genetic trends graphs, there are a few housekeeping items. These graphs are standardized so you can compare selection pressure directly from trait to trait. We set the year 2000 to zero so you can see the relative genetic change during the past 20 years, and how change in each trait compares during that time frame. The trends are only reflective of the purebred Simmental population, so do not include SimAngus™, Simbrah, or Fleckvieh cattle. The graphs are broken into maternally and terminally focused traits based on the year of birth of the animal.


In the maternal traits, there is an impressive balance in increasing calving ease, decreasing birth weights, increasing weaning weights, while decreasing milk and holding mature weight flat (suggesting a reduction in the cost to maintain the cow herd). Take a second to digest all that. It is NOT easy to move genetically correlated traits in opposing directions, yet this population has done exactly that.

The stayability EPD (predicting the proportion of daughters who stay in the herd and have calves annually until at least six years old) certainly increased, but in recent years looks a little more flat. I view the recent trend in stayability from two perspectives. On one hand, it’s impressive to see so much change in so many traits in the right direction, all while keeping stayability in a positive trend (or at least not negative). On the other hand, the stayability genetic trend is something our members — our key decision-makers — need to notice. If Simmental and Simmental cross cattle are to maintain high demand in the commercial sector, the daughters going into cow-calf herds need to stay and be productive. Fertility is the number-one trait tied to profitability in the commercial beef industry.

A challenging component of stayability is that it is a lowly heritable trait, meaning the environment plays a much larger role in the phenotype than genetics do. As such, you can see phenotypes that don’t match the genetic predictions for longevity. This does not mean the genetic predictions are wrong. The genetic predictions for lowly heritable traits are a much better way to select for the genetics of that trait than using a phenotype (heavily influenced by the environment). In other words, to make improvements in the genetic potential for cow longevity (or stayability), selection using the stayability EPD will make much faster progress than simply selecting on a phenotype (e.g., open/pregnant).

When we look at the genetic trends for the terminal traits, we also see positive movement in nearly all the economically relevant traits. Post weaning gain, carcass weight, and marbling are all increasing. We are starting to see an uptick in yield grade, which is not in a favorable direction, but given the breed’s potential for yield, this is not a concern at this time.

The economic indexes also reflect the positive trends we see in these graphs. In the past 20 years, Simmentals have increased by 27% in the All-Purpose Index ($API) and by 26% in the Terminal Index ($TI). This translates to an increase of over $3,000 per bull when making replacement heifers and $2,000 profit potential for terminal use sires.

Here is your moment to pause all of your busy work and think about whether the decisions you are making about your genetic offerings are taking you in the right direction. Do you have a clear focus for your feedstock program? Are you making decisions to support that area of focus? Are you participating in programs that help get the most accurate predictions possible? Is all your hard work and money paying off? Are you moving in the right direction?


When I sit back and reflect on what the Simmental breed has done in the last 20 years, I am impressed with what I see. Our members deserve a round of applause for the improvement of many economically relevant traits that are hard to improve simultaneously.  I see a commitment from our breeders, our board, and our staff to develop programs and tools used to create genetics with commercial relevance and demand. I see these programs and tools leading us in the right direction,  or we wouldn’t see such balanced improvement in economically relevant traits. As you know, it takes years to see the results of beef cattle genetic selection.  With more recent programs like the Cow Herd DNA Roundup, Carcass Expansion Project, and Calf Crop Genomics, I can’t wait to see where the increase of data and data quality will take us next.

 

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