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United States Department of Agriculture

Agricultural Research Service

Healthy Animals Newsletter

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Issue 21, March 2005
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Road to Discovery: Genetic Mapping Lays Groundwork for Cattle Disease Treatments

ARS scientists at the National Animal Disease Center's Bacterial Diseases of Livestock Research Unit in Ames, Iowa, are producing maps that could one day lead researchers to discover preventative and therapeutic treatments for several important cattle diseases.

For example, Mycobacterium paratuberculosis, the bacterium that causes Johne's disease, was sequenced in 2002 by Ames scientists under the direction of ARS microbiologist John P. Bannantine and Vivek Kapur, a researcher at the University of Minnesota's Advanced Genetics Analysis Center.

The sequencing and discovery of several genes will help differentiate the bacterium from other closely related bacterial species and could help in the detection of the disease and development of a vaccine.

Johne's disease, an intestinal disorder characterized by diarrhea and weight loss in infected cattle, is found in 7 percent of beef herds and 22 percent of dairy herds in the United States. Currently, it takes up to six months to identify the bacterium in laboratory culture because M. paratuberculosis grows slowly, which hampers diagnosis of the disease and the progress of scientific research studies.

Bannantine and Kapur are also working to identify antigens from the M. paratuberculosis genome and incorporate the antigens into diagnostic tests so herds can be tested for infection.

Cow.A few years ago, ARS veterinarians Ray Waters and Mitch Palmer at Ames invented a new blood-based assay for detecting bovine tuberculosis (TB) in animals. Bovine TB is caused by M. bovis, which is genetically related to M. paratuberculosis. ARS has received a patent on the test. Since the test only requires a single blood sample, animals are only handled once. The assay works by detecting nitrite in blood-sample cultures because nitric oxide is produced by mammals as a natural response when fighting TB. Although bovine TB is close to being eradicated in the United States, it still poses a significant risk to domestic livestock, wildlife and people worldwide.

Meanwhile, other ARS researchers at Ames have either completed or are actively sequencing additional cattle pathogens.

ARS microbiologist Shirley Halling and Kapur led sequencing of Brucella abortus, a bacterium that causes bovine brucellosis, a highly contagious bacterial disease that induces late-term abortions and infertility in cows. They hope to identify those genes that mediate protective immunity.

Also, ARS microbiologist Richard Zuerner is leading sequencing of the pathogen Leptospira borgpetersenii serovar hardjo, the most common cause of leptospirosis in cattle, using an automated analyzer operated by veterinary medical officer David Alt for rapid analysis of the organism's genes. Leptospirosis causes abortions, stillbirths and weak offspring in cattle and swine. It can also reduce milk production in cows.

These research projects are part of Animal Health, an ARS national program (#103) designed to conduct basic and applied research on selected diseases of economic importance to the United States livestock and poultry industries.

For more information, contact the unit's acting research leader:

Mitch Palmer, Ames, Iowa

Research Briefs

An electrostatic system developed by ARS to reduce airborne dust and microorganisms in poultry houses and hatcheries is being commercialized.
Bailey W. Mitchell
(706) 546-3443

By creating a genetic map of the chicken, ARS researchers joined a Michigan State University biologist, who created the barnyard animal's first physical map, in contributing to the sequencing of chicken genes.
Hans H. Cheng
(517) 337-6758

A new ARS database contains gene sequences that will be used to pursue genomics-based control strategies to counter major poultry diseases.
Hyun S. Lillehoj
(301) 504-8771

Too much protein for lactating cows can contribute to nitrogen pollution and, in some cases, decreased milk yield, according to an ARS scientist.
Glen A. Broderick
(608) 890-0053

A new ARS research center is focusing on meeting the needs of forage-based enterprises in the Mid-South.
James R. Strickland
(859) 257-1647

An ARS researcher and her university colleagues have found copper oxide wire particles effective in de-worming sheep and goats.
Joan M. Burke
(479) 675-3834, ext. 227

Toxic rangeland plants that weaken and kill livestock and wildlife are targeted by a new ARS lab in Utah.
Lynn F. James
(435) 752-2941

Young cloned pigs might not fight diseases as effectively as non-cloned pigs, according to ARS and university researchers.
Jeff Carroll
(806) 746-5353

An ARS research has found that there may be a direct correlation between eggshell quality and Salmonella infection in chickens.
Jean Guard Bouldin
(706) 546-3446

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Last Modified: 2/6/2007
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