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Genetics may supply solution for BRD

Susceptibility to bovine respiratory disease, commonly called BRD, is 19% heritable, according to new research coming out of Colorado State University.

“That’s pretty big,” says Mark Enns, assistant professor of animal sciences at CSU and lead researcher for the project. “Birth weight is one of the most heritable traits, and that’s 40%. Some breeds of beef cattle show only about 20% heritability for milk production, expressed as pounds of calf weaned.”

Enns adds that while the results of the two-year study are preliminary, the implications are far-reaching.

“The goal in this type of study is to determine how much of the differences in animals’ performance is caused by underlying genetics,” he says. “Realizing the possibility of identifying which animals are most likely to require treatment for BRD could have huge economic consequences for the beef industry.”

BRD has shown again and again to be a huge cost to the beef industry. Iowa State University research shows cattle treated one time for the disease weighed 24 pounds less at slaughter than healthy cattle, amounting to an average loss of $23.23 per head.

Sorting out disease

“The ultimate goal here is to develop a selection tool that can help both ranchers and feedyards identify these animals,” Enns says. “We will continue to pick apart the genetics for further study, and this will spawn many more research projects before we’re through.”

According to Enns, producers could use the information in many ways, including separation or isolation in the feedlot, drug and nutritional regimes for susceptible animals, or implementation of such practices as low-stress weaning and minimal handling.

“This also holds huge implications for those in the natural and organic sectors who may choose to simply avoid animals that are susceptible to BRD,” he adds.

And there is obvious potential for breeding programs that may decide to use the information in breed development. One goal of the research team is to use a DNA profile to develop an expected progeny difference, or EPD, for BRD susceptibility.

The BRD project originated with the National Beef Cattle Evaluation Consortium Scientific Council.

“We’re constantly trying to identify those issues that can fill holes and address weaknesses in genetic selection,” explains Enns, “and how genetic improvements can lead to more profits.”

The project’s finding that BRD susceptibility is 19% heritable is but the tip of the iceberg, Enns says. The team is still in the early stages of analyzing data, and the practical application part is yet to come.

“We’ve only covered the feedlot side; there’s still the rancher’s perspective,” he notes. “The ultimate goal of this and further projects is to help save producers money and keep animals healthier.”

Queck-Matzie writes from Fontanelle, Iowa.

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DEADLY FOE: This lung from a BRD mortality in Colorado shows the damage the disease can do. An Iowa study on the economic impact of BRD showed effects on more than half of cattle.

This article published in the April, 2010 edition of BEEF PRODUCERS.

All rights reserved. Copyright Farm Progress Cos. 2010.