Genomics brings a brave new world to the genetic-improvement process. But don't throw your EPDs out just yet.
In a classic country-western oldie, Tennessee Ernie Ford sings of a delicate situation that arose when his potential father-in-law took exception to Tennessee's budding romance with his daughter. “He cocked back the hammer right on the spot,” Tennessee croons. “When the gun went off, I outran the shot.”
When considering their budding romance with the brave new world of genomics, cattlemen might be well advised to ignore Tennessee's advice. Unlike the “Shotgun Boogie,” cattlemen doing the genomics boogie need to be careful they don't outrun the promise of what the technology can do for genetic improvement.
Hypothetically, delving more deeply into the sequence of the bovine genome might reveal a hundred different traits of possible interest to cattlemen. Realistically, says Darrh Bullock, University of Kentucky Extension breeding and genetics professor, “There are going to be four or five traits that are going to be extremely important to the producer.” Most likely, those traits won't change much in the years ahead.
“Look at the terminal-cross guy,” Bullock says. “Regardless of how many EPDs there are, if he's truly a terminal-cross producer and not retaining ownership, growth and calving ease are still his big factors. And that won't change regardless of how much technology we get.”
If you're producing replacement heifers or are concerned with feedyard performance and consumer acceptability, that list is a little longer. “But for any individual producer, I think four or five traits will pretty much nail it down for them,” Bullock says.
So why worry about genomics? Because DNA markers have the potential to make you a better manager of the genetics in your cowherd.
“What genomics is ultimately going to bring to the picture is we're going to get much better (EPD) accuracies at a much earlier age,” Bullock says. That will be especially useful with yearling bulls. Because EPDs are based on both individual and progeny performance, yearling bulls, by definition, have EPDs with very low accuracies for all traits. Even older seedstock bulls with growing progeny data can have low accuracies on lowly heritable and hard-to-measure traits like reproduction and feed efficiency.
And that, in Bullock's mind, is where the real promise lies in the swirl of infatuation currently surrounding DNA marker technology for identifying economically important traits in cattle. In the future, he says, “even when it comes to weaning time, if we have good genomics information, we'll have enough accuracy on a bull to know whether he's good enough to keep as a potential herd sire or whether it would be better to castrate him and market him at that point in time.”
That leads to the second thing that genomics technology brings to the dance: By being able to buy yearling bulls with higher EPD accuracies, commercial cattlemen will be able to do a better job with the traits they want to focus on in their cowherd. Two such traits that are probably universal are reproduction and efficiency; both are hard to measure and lowly heritable. That's exactly the situation genomics is best suited to help.
“We've always said that traits that are lowly heritable and/or hard to measure are the traits that genomics will help us out the most with,” Bullock says, “because it means there probably are relatively few genes that are making an impact on those traits. So, we can at least control the genetic portion of it, maybe through some good genetic markers.”
Take production efficiency for example. “The efficiency of being able to harvest grass with cattle is hopefully something we're going to be able to make progress with in the future. And genomics is one of those areas that is probably going to help us there, because getting that measured as a trait that we trap through genetic evaluation is going to be extremely costly and extremely difficult.”
You can add reproductive traits to that list as well. But even with the ability to better identify cattle strong in reproductive efficiency, you'll still have to cull some open cows. “If genomics were to become a perfect science tomorrow, we would still have to do a great deal on the management side to take care of reproduction,” Bullock adds.
It's reasonable to predict that genomic information will eventually trump EPDs when you're buying bulls and replacement heifers. “The genomics guys have always been saying that eventually a drop of blood will tell us everything we need to know about an animal,” Bullock says. “The technology has advanced so much in such a short period of time that I won't rule anything out as impossible.”
But genomics isn't yet a perfect science, and that means EPDs will continue to be important. In fact, Bullock believes that widespread adoption of genomics information by commercial cattlemen hinges on developing marker-assisted EPDs for various traits.
That's already beginning to happen, with the inclusion of genomics information in the Angus National Cattle Evaluation program. While other breeds will also develop marker-assisted EPDs in time, traditional EPDs based on phenotype will remain the principal selection tool for commercial cattlemen in the near future. “EPDs are a proven science at this point,” he says. “Don't sell EPDs short and just make a conversion to genomics technology.”
Genomics data can be helpful, he says, “but it needs to be used in a balance right now as we're in the process of getting the transition going. The amount (of genomics information) producers need to use in the selection process needs to be tempered somewhat until we get a little more information on it to know just how we're doing. We need the data desperately, but currently we don't need to be, I think, overly focused on that information in our selection process.”
That's an area Bullock sees as a potential roadblock — the dearth of genomics data filtering through the pipeline to help breed associations and researchers further refine the science.
“The sample goes to the genomics company and the information goes back to the producer. There isn't really a good system in place right now to get that data to the associations so it can be utilized in genetic evaluations,” he says.
A template for that data flow already exists.
“We did an excellent job with that with ultrasound by having it go through central processing, basically,” he says. “The data always went to the breed association and then back to the producer. But unfortunately we didn't get that as part of the infrastructure when genomics started coming about. If there's anything we can do to help this whole process along, it's developing better infrastructure in getting data to the breed associations.”
There's an old saying: “You gotta dance with the one that brung ya.” No doubt, EPDs have brought the cattle business a long way and there's no doubt that EPDs will continue to call the tune as cattlemen strive to make genetic improvements in their herds.
But there's a new partner on the dance floor. And the science of genomics is ready to boogie.