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| New rule designed to protect cattle from trichomoniasis | ||
| 09/10/2008 | ||
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ODA's new regulation requires testing of imported cattle The Oregon Department of Agriculture is undertaking a new effort to detect and control an old disease in cattle. A revised regulation for imported cattle, combined with a new way to test for the disease, will hopefully reduce the incidence of trichomoniasis- a protozoan infection that interrupts pregnancies in cows. Some states simply live with the disease in the cattle population. Oregon and other western states are determined to keep it at bay. "We are serious about protecting our cattle industry from trichomoniasis," says Dr. Don Hansen, State Veterinarian with ODA. "The disease has real economic consequences wherever it strikes and there is a good reason we don't want it to spread in Oregon." Trichomoniasis in cattle is different from the human affliction of the same name. People cannot contract the cattle version and it poses no risk to food safety. But its impact on breeding cattle can be devastating to the rancher. "If it were to hit early in the breeding season under certain conditions, the disease could easily cost a 300 to 500 head outfit a half million dollars in a single year due to fewer calves being born," says Dr. Julie Weikel, a field veterinarian based in Burns who is ODA's lead person on trichomoniasis. "There are few family-owned ranches in Oregon that can absorb that kind of hit." Trichomoniasis is a venereal disease that does not cause any clinical illness in the dam or the sire but does mess up the reproductive cycle. Without testing, a rancher would not even know the disease is present in the herd until there are very few calves to sell or many cows calving very late in the season. Trichomoniasis can be highly contagious among cattle. "I have had single positive cases that literally exposed 35 other herds," says Weikel. "The disease has been found primarily in open range counties. In the open range, an individual bull can be picked up literally 30 miles from his home, can expose a lot of herds, and involve a lot of ranches in the process." Oregon has had a control program for trichomoniasis since 2000. Initially, there is no mandatory testing of cattle, but it is in the best interest of ranchers to find out if their herd has the disease. It is a reportable disease, meaning that ranchers and their veterinarians are required to notify ODA whenever trichomoniasis is confirmed through testing. When a positive case is diagnosed, ODA then requires testing of all bulls in the entire herd and bulls in other herds that may have been exposed to the disease. "This past year, we had 35 diagnosed cases of trichomoniasis, 10 of those are out-of-state herds that happened to be grazing in Oregon at the time they were diagnosed," says Weikel. "That's a real concern to us." The new Oregon regulation for trichomoniasis in cattle- adopted by ODA September 1 with the support of an industry advisory committee- deals with importation of herds. Bulls originating from out-of-state must have a negative trichomoniasis test 60 days before coming into Oregon and cannot have been mixed with cows since the negative test. Additional testing is required if the bull comes from a herd diagnosed with the disease during the previous two years. In Oregon, herds testing positive for trichomoniasis the previous year are required to be tested the next year. When the disease is detected, Weikel tracks down all exposed herds and notifies the owners, who will also face a test requirement of their cattle. Other states may or may not require testing of Oregon cattle before their movement into those states. Idaho has mandatory trichomoniasis testing. California and Nevada have recently adopted tough regulations. In states where the herd sizes are large, the tests have not been deemed as critical. "There is not universal concern about the disease," says Weikel. "Certainly, if your cost of production is high enough, you have to worry about it. But there are some parts of the country that have probably lived with trichomoniasis on a regular basis. In those states where they feel they can live with the disease, it is very possible for them to export the disease." That's why Oregon and other western states are being more vigilant about trichomoniasis. There is now a new and improved method for testing. In the past, a swab of the animal was taken and any organisms in the sample were grown out in culture media. That process can take a week before the disease is confirmed, with veterinarians having to look under a microscope daily. A new process involving a PCR technique (polymerase chain reaction) identifies genetic material specific to trichomoniasis and can result in a much faster identification. ODA's Animal Health Laboratory in Salem did joint testing last year using both PCR and the traditional culture process and found the PCR test to produce reliable results within hours. The trend in Oregon shows less trichomoniasis in cattle despite the appearance of just the opposite. "It looks like there is more of the disease than ever when you see all these states, including Oregon, writing these elaborate rules," says Weikel. "But the reality is there is less trichomoniasis. It's just that the attention given the disease is creating more awareness among people who think this is a new situation. If you talk to the old-timers, they will tell you we've had this disease for a long time." That doesn't mean Oregon and other states want to continue a history of trichomoniasis in cattle. With the interstate movement of cattle more common and expedient, the risk of spreading the disease is greater. That requires more vigilance in testing for the disease as well as better animal management practices to reduce potential exposure to other herds. Though not a human disease problem or a food safety issue, trichomoniasis continues to be an economic issue for producers. That's enough for the cattle industry to pay attention. For more information, contact Don Hansen at (503) 986-4680. Story of the Week pdf version http://oregon.gov/ODA/docs/pdf/news/080910trich.pdf Audio Story of the Week http://oregon.gov/ODA/news/080910trich_audio.shtml |
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