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UCD VET VIEWS CALIFORNIA CATTLEMAN, NOVEMBER 2002 Cattle Disease Update
This month we will be meeting in Sacramento for the CCA convention and the cattle health committee will have a busy agenda. I thought I would use this column to give you and update on some of the pressing cattle health issues and encourage each local association to send representatives to that meeting. Vice-chairman Bud Sloan and I would like to encourage you to provide the committee with your concerns if you cannot make the meeting. Tuberculosis In the September issue, Dr. Hamlen and Dr. Davidson-York authored an excellent review of bovine tuberculosis. This included a general review of the disease in cattle, other ruminants, and humans. It also detailed some of the current problems that are being encountered across the nation in the attempt to eradicate TB and contains excellent background information. What is the current status of TB in the Tulare dairy
herd? As of this writing (October 2002), only the original TB-infected dairy herd in Tulare county has been identified. A total of 63 at-risk herds have been tested in the last 5 months. This amounts to over 88,000 individual animals that have been TB tested. Five hundred animals in the quarantined herd have been slaughtered and 250 traceout animals have been slaughtered and examined. The quarantined herd has been tested a second time and will be tested on a periodic basis. Additional herds will be tested and it is possible that other animals or herds may be found to be infected. We will received a full report on this problem at the CCA convention in Sacramento. The short answer is yes it may very well affect all of California, both the dairy industry and the beef industry. California was officially designated to be free of bovine TB in 1999 by the USDA. Before that time (1999), the last case of bovine TB in the state was in 1991. If another cattle herd is found to be infected our official status will drop to “Modified Accredited Advanced”. Also, if the affected dairy in Tulare County chooses to try to “test out” of the current infected status versus depopulating the herd, California would lose our TB Free status. To maintain the current TB Free status, the USDA requires that the affected dairy herd be depopulated (all cattle go directly to slaughter) and there be no spread of TB in California (no new cases in cattle). If we lose our TB Free status, that change would probably occur in early 2003. The change to “Modified Accredited Advanced” status would mean the following: all of California’s breeding cattle more than 6 months of age and older would be required to have a negative TB test within 60 days of interstate movement OR be from a TB “Accredited Free Herd” OR move directly to slaughter. This would include the cattle herds moving to neighboring states on the “pasture to pasture” permits. Even though these “pasture to pasture” permit herds move as a single herd, TB testing would be required. It is important to realize that TB testing takes 3 days. The intradermal (in the skin) injection of tuberculin is given and the result is “read” by an accredited veterinarian at 72 hours (plus or minus six hours). So the beef cattle have to be held after the injection and run through the chute again 3 days later. The TB test usually costs 5-10 dollars per head depending on local conditions. Currently, breeding age dairy cattle (6 months of age or older) leaving California for other states are already being TB tested before being shipped. The discovery of more TB infected cattle herds could lower our status further to “Modified Accredited” status with further requirements for testing and additional movement restrictions. What are CDFA and USDA currently doing with regard to
this TB problem? The short answer is everything possible. We are lucky in California to have some of the best animal health officials anywhere in the U.S. and they have been working hard on this problem. Below is a partial list of CDFA and USDA activities directed at this problem. 1. The Tulare county dairy is under quarantine. All cattle in this herd are TB tested about every 60 days. Cattle are only allowed to leave this herd to go to slaughter at a USDA inspected plant. 2. All cattle sold from the affected herd are being traced and all those dairy herds are undergoing whole herd TB tests. The chart in this column summarizes the testing efforts to date. 3. CDFA and USDA are both working hard to get the word out to producers, veterinarians, and all industry groups. The column in last month’s magazine is just one example. 4. As all the trace back information becomes available the USDA will conduct a full review of the problem. 5. The USDA has developed Uniform Methods and Rules for Bovine Tuberculosis Eradication and has put these “rules” out for public comment. CDFA is making comments on these “rules” to help minimize impacts on the beef cattle industry and to make the cattle TB eradication program as efficient as possible based on the most current scientific facts and principles. What is the California Cattlemen’s Association
doing about this problem? CCA was notified of this issue early on and has been extremely active, just a few of the efforts are listed below. 1. CCA staff works daily with USDA and CDFA to express the concerns of the beef cattle industry to these agencies. 2. Through many methods (Hot Irons, information packets to local associations, the CCA magazine, committee meetings, etc) CCA has been keeping everyone informed. This doesn’t include all the information relayed to individuals who phone in with questions. 3. In July, Washington State was going to require that all cattle coming from California be TB tested before entry into their state. One of the large auction markets in northern California was essentially crippled by this requirement. CCA staff intervened and solved this problem in a matter of a few hours on a Friday afternoon. The importance of this type of effort to all beef producers is very large, indeed. 4. CCA is also working on submitting comments to the USDA with regard to their TB eradication “rules”. Their goal is to minimize any negative impacts on the beef producers while maintaining a viable and effective TB eradication program. Are people becoming infected with TB from this
California cattle outbreak? The simple answer is no! Milk from the infected dairy was always pasteurized (pasteurization kills the TB organism). Slaughtered cattle with TB from this dairy were condemned and not put into the food chain. The dairy workers were tested and there is no evidence to date any became infected from the cattle on this dairy. Public health officials state there were over 3,300 new cases of TB in humans in California last year alone and that none of these were traced to TB infected cattle in the U.S. Additionally, it is important to understand that routine TB testing of people working in restaurants in California is an important step in the prevention of TB cases in humans. This measure is not routinely applied to restaurant workers in our counties. In my opinion, this public health disease prevention measure is as important as TB eradication in cattle and should be pursued with the same vigor.
What can you do to keep TB out of your herd? There are a number of important steps you can take. 1. Support your cattlemen’s associations. No one has the time to do all the necessary work on these issues by themselves. Only through the efforts of your associations can you have a voice for your concerns and someone to represent your interests. 2. Contact your veterinarian, he or she is an excellent source of information about this complicated disease. Also, your veterinarian can help you with practical measures to improve the biosecurity of your herd. 3. Follow the animal import regulations. These are designed to help prevent the introduction of new diseases into your herd, including TB. 4. Know the TB status of the herds you purchase cattle from (including any mandatory TB testing that has been done in those herds). 5. If you share grazing land with other cattle (dairy or beef), know their TB status. 6. If you graze adjacent to Mexican-origin cattle, they are a potential risk for exposure to TB. Maintain excellent fences in these circumstances and increase biosecurity measures if Mexican-origin cattle graze adjacent to your herd. 7. Maintain permanent identification of your cattle and record animal movements into and out of your herd. It is everyone’s hope that the impact of this TB infected dairy herd will be minimal; however, it does prove the point, “that an ounce of prevention is worth a pound of cure”.
John Maas, DVM, MS
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