USDA’s Agricultural Research Service recently announced their scientists had identified a genetic “marker” linked to three diseases prevalent in feedlot cattle. The ability to identify breeding cattle that could pass susceptibility to pinkeye, foot rot and bovine respiratory disease to their offspring could save producers millions of dollars a year, and is another example of how the emerging science of DNA sequencing could bring yet more efficiency and cost benefits to the industry.
There’s a lot more to learn, according to Dr. Hayden Brown, Professor of Animal Science at the University of Arkansas. Although, “a gene that is a major gene, that has a real impact of the phenotype of that particular trait,” would invariably point to a particular characteristic, Brown told Ozarks Farm & Neighbor that, “in most cases we’re talking about a DNA sequence, or part of a gene that’s associated with a genotype. The science hasn’t matured relative to that; we’re still in some development stages in regard to how useful some of those markers are going to be in terms of cattle breeding.”
One area where Brown believes genomics can be utilized to enhance breeding of commercial cattle is in determining whether a bull is effectively mating cows during a defined breeding season. “You can use genomics to determine parenting, and that gives the producer an opportunity to identify those bulls that aren’t working, and make some management adjustments in that regard,” he explained. “The use of genomics to determine what parentage works best for those producers who find themselves needing to use a multisire breeding program, so that way they can determine which bulls are actively seeking out estrus cows and mating, and that could be helpful in managing a bull battery.”
Producers can also use identified common traits to separate cattle into management groups; for instance, markers have been developed to identify cattle that are susceptible to the toxic effect of grazing endophyte infected fescues, so those cattle can be placed on alternative forage. Other genetic sequences are known to signal the likelihood of marbling in feedlot cattle.
This information is already available to producers, at a price. “We would like to see those fees decline a little bit before it’s going to gain widespread acceptance, I think, in the commercial cattle industry,” said Brown. “Most of these companies that are making this technology available have a tremendous amount of investment in getting to this point, and I’m sure they’re trying to recover some of that investment.”
Brown said seedstock producers can also use markers to increase the accuracy of breeding value prediction. Dr. Daniel Stein, Extension animal breeding and selection reproduction specialist at Oklahoma State University, said while producers will still rely upon EPDs, genomics will enhance their accuracy. Stein told OFN, “I can take a heifer calf, take a genomic sample, send it in, and have those EPDs calculated and genetic merit of those EPDs as far as accuracy. I do not have to have a number of progeny on the ground to generate the same accuracy EPDs that I can get from a genomic sample right up front.”
The EPDs most relied upon in this region are those related to birth weight and calving ease; as Stein said, “I need to get a calf on the ground before I can do anything else.” It can get complicated trying to keep up; the American Angus Association updates their EPDs weekly, and Stein said, “With the genomic information we have, information is changing daily. We are enhancing the accuracy of those EPDs. If I can increase the accuracy and narrow that possible change window to predict the true merit of that individual, then that genomic information is good early on.”
It can also get complicated to compare EPDs across breeds. USDA’s Meat Animal Research Center at Clay Center, Neb., publishes an across-EPD adjustment factor annually, but Stein said that data is lacking in accuracies. He said, “If I’m comparing EPDs between individuals, all I’m looking for is a ballpark estimate. Say I’ve got an individual at 90 percent accuracy on a trait I’m comparing with, on a crossbreed EPD adjustment factor, with a 30 percent. I can look at that crossbreed comparison and come up with, ‘There’s this difference’ or, ‘They’re the same,’ but there’s a possibility of more movement on that lower accuracy versus the higher accuracy individual. Each breed publishes a possible change chart that’s associated with each EPD, so I have to do a little bit of homework to see what the possible change is within a breed, at a certain accuracy.”


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