Being able to accurately estimate disease risk would be very helpful to veterinarians, but often the right tools are not available to get this done. Mike Sanderson, DVM, MS, Kansas State University, and graduate student, Becky Smith, DVM, have developed two disease-risk models, however, that may be able to help veterinarians estimate the risk of bovine viral diarrhea virus (BVDV) and trichomoniasis caused by Tritrichomonas fetus.
“BVDV seems to be a hot topic so in some cases it may get blamed for more than it does,” Sanderson notes. “Trich is a growing problem and I think veterinarians are becoming more aware of it again. Correctly estimating herd risk is a complex and difficult issue. These new models are meant to help veterinarians and producers make the most economical decisions about how to control that risk.” Both of the models can be used to identify the optimal testing and vaccination strategy for a given management plan to control the risk of introducing trich or BVDV. They might also suggest where management could be changed to decrease risk.
Trichomoniasis, a venereal disease that can cause early abortions, has been fairly isolated in geographic pockets until a few years ago. “A few years ago no one thought trich was much of a problem, but it seems to be re-emerging and moving into areas where it hadn’t been recognized in some time,” Sanderson explains.
The Trichomoniasis page of the website asks specific questions under the categories of herd management, imports and neighboring herds. Once the information is entered, the program calculates the probability of introducing trich and the probability of exceeding a certain amount of cost associated with the outbreak.
For BVDV specifically, the model will help identify the most economical long-run testing and vaccination control strategy including which animals to test. “Often targeted testing of imports — especially fetuses of imported pregnant females — is the best testing plan and additional testing doesn’t always pay to decrease entry risk,” Sanderson explains. “There are many scenarios where just testing the whole calf crop every year is not the most economical choice. The web model doesn’t directly address the scenario where you know you already have BVDV. In that case, you probably need to test calves to get rid of it first.”