Texas singled out for cattle brucellosis, but may advance soon

Cattleman, The, Sep 2007

Texas was officially singled out as the only state not free of cattle brucellosis on July 23, when Idaho regained its classfree status from the U.S. Department of Agriculture.

Texas, due to undergo a USDA review of its brucellosis program, also may achieve "free" status by the year's end.

Cattle brucellosis, a bacterial infection, does not pose a threat to food or pasteurized milk products, but it can cause cows to abort or deliver sickly calves. The brucellosis-free status allows cattle to be moved across state lines without a test for the disease.

"Idaho eradicated cattle brucellosis in 1991. Infection in cattle resurfaced in 2005, spread by infected elk from the Greater Yellowstone Area. Idaho lost its 'free' ranking in early 2006," said Dr. Bob Hillman, former Idaho state veterinarian. Since 2003, Dr. Hillman has served as executive director of the Texas Animal Health Commission.

"Thousands of cattle have been tested for the disease in Idaho, and the USDA has determined that the state is again officially free of the disease.

"We have not found an infected cattle herd in Texas in more than a year," Dr. Hillman continued. "In 2006, the TAHC convened a Brucellosis Eradication Working Group, composed of about 40 cattle industry members.

"The group evaluated all aspects of Texas' brucellosis program, to ensure we had done everything possible to eradicate the disease and to prepare for our Texas USDA review.

"The USDA brucellosis review has been requested, and if we do not identify any additional brucellosis-infected herds, Texas could be declared brucellosis-free by the end of the year."

Dr. Hillman said that brucellosis testing of adult cattle at livestock markets must continue for at least two years after the state gains "free" status, as a way to find infection that may have yet gone undetected.

As added protection, he suggested that replacement heifers-those heifers kept, purchased or sold for breeding-continue to be vaccinated with RB-51 brucellosis vaccine, especially in the eastern portion of the state.

"The vaccination of heifers between the ages of four and 12 months has been voluntary and at producer expense since 1996," he said. "The cost can be a wise investment to protect herd health, just in case there is undetected infection in the state.

"The vaccination also can add value to breeding heifers and meet current requirements for selling Texas heifers in a number of other states."

The key to successful brucellosis vaccination is timing, noted Dr. Hillman. Heifers must receive their dose of RB-51 prior to being exposed to brucellosis bacteria, a situation that can occur when an infected cow in a herd aborts or delivers a calf.

Naturally curious, heifers and other herd mates will nuzzle or lick the fetus or newborn, ingesting the millions of bacteria shed by the infected cow.

Brucellosis-infected heifers will thrive and appear normal, harboring infection until they are cows, when the disease cycle is repeated.

"In the 1950s, the country had at least 100,000 brucellosis-infected herds, with 20,000 of those in Texas," said Dr. Hillman. "It's obvious we've made tremendous progress.

"We're in a race, not just to eradicate brucellosis, but to maintain Texas' credibility as the country's top cattle production state. Replacement heifer vaccination, good recordkeeping and concern for Texas' cattle health status can help achieve these goals."