University of Wyoming Extension News

UW seeks better brucellosis control through vaccine development, vaccination practices

Ph.D. student Alexis Dadelahi and undergraduate student Matthew Rorke conducting brucellosis research at the University of Wyoming.

Ph.D. student Alexis Dadelahi and undergraduate student Matthew Rorke conducting brucellosis research at the University of Wyoming.

College of Agriculture and Natural Resources scientists at the University of Wyoming are hopeful their brucellosis studies may produce a better vaccine for livestock and are studying whether a change in vaccination procedures could offer better control.

Brucellosis can cause elk, bison and cattle to abort fetuses. The highest risk of brucellosis transmission to other animals occurs after an animal has an abortion. The organism can also be transmitted to humans, often through consumption of unpasteurized milk or dairy products such as soft cheese, which may result in a severe disease called undulant fever.

Brucellosis is an exotic disease that came from Europe and European cattle and was then transmitted to wildlife in the U.S., establishing the reservoir in elk and bison seen in the Greater YellowstoneArea.

“We have eradicated the disease from livestock but occasionally get a disease spillover from elk transmitting the organism to livestock,” said Bruce Hoar, University of Wyoming brucellosis research coordinator. “One of the ways we try to control brucellosis is through the use of vaccinations.”

Scientists are interested in pursuing vaccines for wildlife, particularly elk; existing vaccines for cattle are not very effective at preventing disease in elk. The emphasis, though, is on livestock vaccines, said Hoar.

Cattle in the U.S. have been vaccinated since the 1930s with a vaccine called Strain 19. That vaccine was moderately effective preventing 60-70 percent of cattle from aborting after becoming infected, said Hoar. Strain 19 was replaced by a vaccine called RB51 in the 1990s and is the currently licensed vaccine for cattle.

“It, too, only protects 60-70 percent of animals in the herd, so that leaves 30-40 percent of the herd vulnerable, and, because of that, we are looking for better vaccines, and that is what a team of researchers here at the University of Wyoming have been involved in for a number of years,” said Hoar.

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UW Extension publication shows cost estimates to build stackyard fence

Cost estimates and benefits of fencing haystack yards to limit attracting elk and possibly decreasing brucellosis risk to cattle are described in a new bulletin from the University of Wyoming Extension.

Researchers in the Department of Agricultural and Applied Economics at the University of Wyoming provide cost breakdowns for a stackyard fence that meets Wyoming Game and Fish Department (WGFD) construction recommendations. The publication is The cost of brucellosis prevention: Fencing stackyards, B-1232.

The WGFD provides fencing materials where elk-cattle commingling is a concern; the producer covers installation costs. The bulletin provides total cost of materials provided by the WGFD, total tools and materials cost not provided by WGFD and estimated labor.

The publication is available free on the Internet.  Go to www.uwyo.edu/ces and click on Publications on the left-hand side of the page. Click search bulletins and enter B-1232 in the Publication Number field.

Brucellosis testing and research expanding in Wyoming

University of Wyoming Laboratory Assistant Tracy Dunn performs diagnostic testing for brucellosis at the Wyoming State Veterinary Laboratory. In October, the state veterinary laboratory tested nearly 9,400 animals for brucellosis.

When two heifers on a ranch near Meeteetse tested positive for exposure to brucellosis this fall, technicians from the University of Wyoming State Veterinary Laboratory quickly tested more than 320 other cattle in the area in addition to the 250 tested in the source herd and determined that the disease had not spread.

A year earlier, more than 4,200 animals were tested shortly after brucellosis was reported in northern Wyoming, said Walt Cook, who coordinates brucellosis research at UW.

The ability to conduct such rapid testing is one example of how legislative support to combat brucellosis is paying off to the benefit of the state’s cattle producers, Cook said. He said brucellosis is a bacterial disease that can cause domestic cattle, elk and bison to abort their calves. Elk and bison of the greater Yellowstone area of Wyoming, Montana and Idaho are a reservoir of brucellosis in the United States, so the disease is a concern for cattle producers in that area.

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