Attn:Texas Cattle Ranchers

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Texas Animal Health Commission
Box l2966 • Austin, Texas 78711 • (800) 550-8242 • FAX (512) 719-0719
Bob Hillman, DVM • Executive Director
For info, contact Carla Everett, information officer, at 1-800-550-8242, ext. 710, or [email protected]

For Immediate Release -- May 14, 2004

Cattle Tuberculosis (TB) Testing Lags,
Could Impact Reinstatement of Texas' TB-Free Status

Dairy and purebred beef cattle owners must complete the task that we agreed to accomplish by stepping forward to have herds tested for cattle tuberculosis (TB), if Texas is to regain Class "Free" status for TB eradication, warns Dr. Bob Hillman, Texas' state veterinarian. As of early May, 349 Texas dairies and 115 purebred beef herds have been tested for the bacterial disease since November 2003. While the dairy industry is making significant progress, it still falls far short of testing necessary to assure the U.S. Department of Agriculture (USDA) and other states that Texas has conducted adequate disease surveillance to find any remaining infected herds. Texas' TB plan, developed in 2002 by a joint industry and regulatory working group, calls for testing the state's 850+ dairies and at least 2,500 of its beef seed stock herds by the end of August 2004. The plan was submitted to the USDA, along with a commitment to comply with the program.

Since l983, cattle TB has been detected in 15 Texas dairies and six purebred beef herds. In 2000, Texas attained the TB-free status under the National Tuberculosis Eradication Program, but lost it in 2002, after two infected herds were detected. Dairy and purebred beef cattle are no more susceptible to TB than commercial cattle, but they usually are maintained in a herd much longer, due to their value for milking or breeding. Once exposed to cattle TB bacteria, it may be several years before dairy or purebred cattle are tested, or are culled and sent to slaughter, where carcasses are examined. (Milk is safe to drink, because required, routine pasteurization kills TB bacteria.)

"The U.S. Department of Agriculture (USDA) could deny a bid for Texas to regain TB-free status, citing lack of disease surveillance, if we don't meet our testing objectives," explained Dr. Hillman, who heads the Texas Animal Health Commission (TAHC), the state's livestock and poultry health regulatory agency. "The TAHC, through a cooperative agreement with the USDA, is funding 'fee-basis' payments to private, certified veterinarians who conduct herd tests, eliminating out-of-pocket expense for the cattle owner. Unless we are granted an extension, this federal money will not be available after the end of August, so it's crucial that producers take action to schedule a test now."

"The herd test must include all cattle 24 months of age or older (including dry cows in dairies). Testing of purchased replacement animals is optional, but the cost is covered by the program and should be considered," said Dr. Hillman. "To conduct a test, the certified or regulatory veterinarian will inject cattle with a small amount of tuberculin in the skin of the caudal fold, an area on the underside of the tail. Seventy-two hours later, the veterinarian will visually and manually examine the injection site for a reaction, such as a thickening of the skin. A response is an indication the animal may have been exposed to TB bacteria."

Around three to four percent of dairy cattle and about two percent of beef animals will respond to the caudal fold skin test. Until recently, a second 72-hour skin test, called the 'comparative cervical test,' was needed to differentiate between an animal's exposure to cattle TB bacteria, or to avian TB, which is not a danger to herd health. The recent approval of the Gamma Interferon test has greatly simplified this follow-up testing process. Now state or federal regulatory personnel collect blood samples from 'caudal fold' responder cattle so Gamma Interferon tests can be run at the State-Federal Laboratory in Austin. Of more than 3,800 Gamma tests run during this testing program, about .34 percent­or 132--have been in the suspect or reactor range.

"Animals also positive on Gamma test will be purchased by the USDA for slaughter and necropsy. Internal organs will be examined for lesions compatible with TB, and tissue samples will be submitted for confirmation to the National Veterinary Services Laboratory in Ames, Iowa," said Dr. Hillman. He noted that the USDA's indemnity is based on the fair market value of the animal. For adult dairy animal, agricultural economists have determined the standard appraisal to be $1,425. Beef animals are appraised individually by a certified appraiser. Producers, however, may negotiate for a higher payment by providing registration papers for registered cattle and/or production records for dairy cattle. The USDA also will pay for hauling and disposal or burial of the carcass.

If infection in the herd is confirmed, the owner has two options. The herd can be quarantined and undergo a series of retests, until all infected animals have been removed, and subsequent repeated testing assures that infection has been eliminated. Or, the USDA will negotiate a purchase price for the herd and depopulate the animals, allowing the owner to return to normal business practices more quickly.

"Clearly, cattle TB must be addressed in Texas­and in other states where infected herds also have been detected. This currently includes California, New Mexico, Arizona, Kansas and Michigan. In Texas, we need the support of dairy and purebred beef producers to find infection, if additional infected herds are present; prevent further spread of disease; and regain our ability to move breeding cattle across state lines without a TB test," Dr. Hillman noted. "Allowing cattle TB to gain a 'hoof-hold' would be extremely costly, in terms of credibility with consumers, and in our ability to trade freely with our interstate and international trading partners."

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