USA - Washington joins states that require TB test for imported dairy cattle

On March 15 Washington state will join 34 other states that require dairy cows and dairy bulls six months of age or older to test negative for cattle tuberculosis (TB) within 60 days before entering the state. Dairy heifers and bull calves under six months of age being brought into Washington state will have to be officially identified with an ear tag and will be restricted at a facility designated by the state veterinarian until they test negative for TB at six months of age. The only exceptions will be for dairy cattle that originate from herds accredited TB free according to the Uniform Methods and Rules for Bovine TB (January 2005) and dairy cattle delivered for immediate slaughter at a federally inspected slaughter facility. Other than cattle destined for immediate slaughter, all dairy cattle six months of age and older must have a certificate of veterinary inspection, issued within 30 days prior to entering the state, with accompanying test results and a permit issued by the Washington State Department of Agriculture. This requirement is necessary because of several cases of Bovine Tuberculosis in Arizona, California, New Mexico, and Michigan in the last two-and-a-half years. Prior to that, in 2001, Bovine Tuberculosis was detected in two herds in Texas, causing that state to lose its TB-Free status. Bovine TB is a contagious bacterial infection of cattle caused by Mycobacterium bovis. The disease is also contagious to humans. The organism is transmitted by expired air, sputum, feces, urine, milk, and vaginal discharges. The animals can spread the organisms in the early stages of disease. The disease is most commonly spread by inhalation among confined animals, such as in dairy operations. Since dairy animals are often long lived, infected animals can develop lesions in the lungs, lymph nodes and other organs and spread the disease to other dairy cattle. Although state or federal meat inspectors examine the carcasses at slaughter, collecting tissue samples for testing and condemning meat unsafe or unfit for human consumption, by that time the disease has already spread to other animals. Because there is no effective treatment for TB in livestock, infected herds must either be destroyed under government supervision, or the herd is placed under quarantine and tested repeatedly over a period of months, depopulating any animals that test positive. After being released from quarantine, the herd must be tested annually for five years to ensure the animals remain free of the disease. Often, the best option is depopulation, as this eliminates the potential for the disease to reoccur or spread. Thus, in order to prevent the introduction of tuberculosis into the State of Washington, we have instituted the TB testing of incoming dairy cattle and increased surveillance at slaughter plants.