Holly Neibergs, Washington State University, described the progress made so far by a team of university and USDA specialists working to find genes in dairy and beef cattle that impact this health problem.
In beef cattle, the traits in question appear to be moderately heritable and of extreme economic impact. These factors will provide means and motivation for producers to address the traits with genomic selection.
The annual cost of BRD, estimated at about $1 billion, is often the difference in profit or loss for our colleagues in the feedlot sector. The bovine respiratory disease complex is just that – complex. So addressing it only with genomics is unlikely to totally cure the diseases involved.
Still, a handful of brilliant scientists across the country are well on their way to finding genetic variations that may improve cattle resistance to BRD. And this would be big news.
Selecting for health
In practical terms, a few years from now, cow-calf producers may be buying bulls to bring this trait into their herd. And then they may be confidently selling feeder calves with a provable set of DNA markers on BRD, along with other traits, that benefit feeders through lower cost of gain, reduced health costs and higher quality.
There are several stages we will need to get through for this to become reality. But the future of beef genomics is exciting.
Understanding the role of DNA markers in fertility will help the beef industry too, for at the intersection of health and fertility is reproduction.
Here is a true story. Pawnee Chief was a champion dairy bull. His genetics significantly increased milk production and were used broadly across the dairy industry. Over time, it seemed his daughters had fertility issues. “Aha,” said the experts, “high milk equals lower fertility.”
But that was not the case. DNA testing of Pawnee Chief and his son Walking Mark revealed the pair had passed on a novel gene defect that caused spine development to fail in early developing embryos.
This was a lethal mutation. The females were showing as “open.” Instead, the embryos had died. In fact, the apparent loss of fertility was more related to this defect than it was to the increased milk production.
Other similar instances have been found and will continue to be discovered on the new frontier of genomics.
In the works
Today, scientists across the country are analyzing patterns of genes from 20,000 cattle and more than 220,000 gene markers they suspect may have an impact on fertility, health and production. We have invented a special DNA biochip for them to use in this research.
Some of what they find will not be meaningful. But we are excited at the prospects they will identify many genes impacting the bottom line of every cattle producer in the U.S.
They are busy analyzing the data as you read this article. When their findings roll out at upcoming scientific conferences, the experts will debate the results. And as they validate findings, DNA test companies will put the new markers on the market for producers.
Many of these gene markers will have a direct impact on health. For example, the BRD study Neibergs reviewed is part of this project. But many other traits are on the radar, too. A big area of research is fertility.
This is of great interest. Statistics cited at the Beef Improvement Federation symposium and convention indicate the U.S. beef herd average for weaning rates is about 85 percent. It is easy to suppose the industry could add 5 percent to 10 percent to that stat simply by using DNA to select more fertile heifers.
On the ranch, reproduction is a key metric. But measuring fertility rates is completed late in the life of the cow. And with sire EPDs, it takes years of monitoring the progeny of a bull to arrive at accurate EPDs. These are costly data to collect. Instead, it saves a lot of time and money to DNA-test a baby calf to predict the fertility of his or her progeny.
Sires and dams can be selected for health and production traits which help producers rapidly improve their cow herds. Along with good management decisions, these tools can help optimize costs and improve revenue in the cow herd.
A key point is: Cost control is going to be more important as the cattle cycle plays out.
One of the best ways to reduce production costs in a cow herd is to increase conception and birth rates, thereby reducing the number of replacement females needed. Decreasing the replacement rate and costs associated with that on the enterprise reduces unit cost of production or breakeven on calves.
Producers will retain more cows that have calves well past the cow’s breakeven point. They also will raise more calves, so producers can spread fixed and variable costs across a broader economic base. Finally, they have a bigger calf crop to wean and sell, with herd DNA results that back up the calves’ inherited production and finishing potential.
DNA testing for heifer pregnancy, calving ease, birthweight and stayability is now available to producers at affordable costs with high accuracy. And steers being qualified into value-add programs based on their DNA results for their heifer-mates’ average daily gain and marbling.
This is happening in the market now. So it is easy to think out loud that the industry might also put a value on BRD resistance or other cross-sector beneficial traits.
The future of genomics is bright
Many other DNA tests that reflect cattle health and inherited diseases are routine today. The GeneSeek laboratory of Neogen Corporation currently has compiled hundreds of gene variations affecting health in cattle worldwide and has installed them onto tests that screen DNA of seedstock. Many seedstock associations require genetic health tests as part of their registration process.
Cow-calf producers can take similar, practical steps. During breeding soundness exams, vets can pull DNA samples on the bull battery. These samples can be screened later to find the best sires and pinpoint sources of difficult births or genetic defects. Saving one calf easily pays for scanning DNA on a batch of bulls.
Another way to save money is to improve feed efficiency. Several large efforts are underway to apply DNA tests to improve beef feed conversion. Robert Weaber, Kansas State University, has published estimates that improved feed efficiency would save the feeding industry $1 billion per year. That is a lot of new wealth that could be shared between the cow-calf and feedlot sectors.
Today’s DNA tests not only make this practical and possible, but the genome of an animal is not altered when title of ownership changes. Thus, the basis is there for the industry to transmit value for improved health and production characteristics.
Taking advantage of that improved potential will be up to today’s professional, knowledgeable beef producer. 
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Stewart Bauck
- General Manager
- Neogen Corporation
- Email Stewart Bauck
