The BVD Control and Eradication Project (BVDCEP) is a joint effort of WSU Extension, Vet Clinical Sciences, Animal Sciences and the Washington Animal Disease Diagnostic Lab (WADDL) funded through WSU Extension’s Issue-focused Teams Initiative. The goal of BVDCEP is to promote cow-calf herd health by facilitating implementation of infectious disease control Best Management Practices and herd screening for BVDV persistently-infected (BVD-PI) animals to control and reduce the prevalence of BVDV in Washington’s cow-calf herds.
Spring calving season herd enrollment and testing was complete by June and we are now gathering information from the operation risk assessments and management surveys completed by each producer. A total of 7020 animals were tested from 48 herds across Washington. A total of 5917 calves and 1103 ‘other’ (bulls, yearlings etc) were tested. This is half the number of animals we were planning for in this pilot project and represents less than one percent of cow-calf herds in the state. There are currently two fall calving herds that are enrolled to be tested. It’s not too late to enroll for this fall or next spring! The table below shows the distribution of herds that were tested by herd size, the number that had at least one BVD-PI calf and how well our current sampling of herds represents all herd in Washington based on NASS statistics from 2006.
The NASS 2006 column represents the number of herds reported in the state in 2006 by USDA National Agricultural Statistics Service and the % Herds Tested column indicates the percentage of all herds in that herd size category that were tested this spring. The take home message from those numbers is that only 0.5% of the herds in the state have been tested, so it is not possible to draw general conclusions about BVD-PI prevalence in all herds of the state at this point. We need more herds!!
Of the 48 herds that were tested 7 (14.6%) had at least one BVD-PI positive calf, while none had any other cattle (yearlings, bulls etc) test positive. The number of BVD-PI calves in a herd ranged from a single calf to 43, however, most had only a one or two. The prevalence of BVD-PI calves was 1.35% when the single high prevalence herd was included and 0.63% when it was excluded. The lower prevalence is still 2 to 5 times higher than previous reports from individual states and feedlot entry studies. The higher prevalence we observed may be associated with the reasons why a particular herd decided to enroll and may change as the number of herds sampled increases. It would not be surprising if the prevalence of young calves in cow-calf herds was higher that that observed in animals entering the feedlot as one would expect fewer BVD-PI calves would survive to that point. The herd prevalence (14.6%) was also higher than reported in other studies (3-5%), however, it is important to consider the reason why herds chose to enroll in BVDCEP and be tested. Upon completing the evaluation of the operation risk assessments we will have a better idea, however, there were a number of herds that enrolled in the program because they recently had a test-positive animal or their veterinarian suspected they may have BVD in the herd and encouraged them to test the whole herd. That being said, at least 2 of the 6 test-positive herds were fairly confident that their herd was clean and were enrolled in the program to “prove what they already knew” and perhaps gain some market advantage. It is interesting to note that the two herds that had a high prevalence of BVD-PI calves were not routinely vaccinating for BVD.
The economic impact data are currently being collected so that we can provide an estimate of the cost of having a BVD-PI calf in a Washington herd and the potential benefit of participation in the project.
The BVDCEP will continue through June of 2009 and we will continue to enroll herds and provide subsidize testing until the funding comes to an end. However, for this pilot project to be a success we need to enroll more herds and we also need a commitment from cattle producers and feeders to move this project to a program that will continue long into the future and achieve the goals of BVD control and eradication. For more information or to enroll your herd for this fall or next spring contact Dr. John Wenz at 509-335-0773 or jrwenz@vetmed.wsu.edu or visit the program website at: http://www.vetmed.wsu.edu/BVDCEP/ .
Source: John R. Wenz, DVM, MS, Washington State University College of Veterinary Medicine