Identification of Breeding Herds

Non-Technical Summary: The IVMA/ICA Preconditioning Program involves veterinarians in a process that adds value to their beef breeding client's product. As researchers at the ISU CVM, our aim is to conduct research that should enable the Preconditioning Program to add even more value to that product. A large scale project allows us to estimate how widespread and common BVDV exposure is, enabling the industry to prioritize health management issues. Purpose (year 1): This phase of the study is designed to measure the prevalence of exposure to BVDV in Iowa green tag calves and to identify risk factors for such exposure. Knowing the prevalence of exposure to BVDV will enable policy makers to determine the value of possible BVDV monitoring and eradication programs. The risk factor analysis will help veterinarians and producers to control or reduce the risk of BVDV-associated disease. Purpose (year 2): It is reasonable to expect that some herds that are sero-positive are BVDV-PI negative and some sero-negative herds will be BVDV-PI positive. This study will closely examine a subset of these herds to determine factors associated with misclassification. <P> Approach: 1) We anticipate using the IVMA Green/Gold tag program as a contact for veterinarians, if the committee is supportive. Participating veterinarians would enroll clients regardless of participation in IVMA Green/Gold tag program. Options to recruit veterinarians would be discussed with the IVMA Bovine committee but include a.Insertion of program information into IVMA Green/Gold tag program correspondence prior to fall b.Phone calls to veterinary practices from the study staff. 2) Participating veterinarians would identify clients for the program and explain the project goals. The investigators would ensure that all participating veterinarians are familiar with the program outcomes and participant expectations. 3) In fall 2005 participating herds would bleed 12-14 unvaccinated 2005 spring-born calves. Producer's would complete a biological risk management survey and record weaning weights. 4) Sera, biological risk management survey and weaning weights would be submitted for processing and data entry. Sera would be tested for the presence of antibodies to BVDV Type 1 and 2 using virus neutralization (VN). To save costs we will pool two animals. The rationale and effect of pooling on sensitivity and specificity are discussed in the budget justification. 5) Testing will not be charged to producers / veterinarians. 6) Industry outcomes: Prevalence of evidence of exposure to BVDV in Iowa herds and risk factors associated with BVDV exposure. 7) Veterinarian outcomes: Serology results and biological risk management survey results will be provided to the veterinarians of producers that also reported weaning weights, pregnancy rates and completed the biological risk management survey Producers/veterinarians may decide to try to identify the presence of a BVDV-PI by ear notching all calves born in spring 2006, cows that do not produce a calf in 2006, replacements and bulls used in 2006. The herds should also 1) Keep 5-10 calves born in spring 2006 unvaccinated until fall 2006. The producer will pick the calves designated to receive no vaccine. These animals will be bleed and sera tested in fall 2006. 2) Ear notch all dead calves between birth in spring 2006 (also stillborns) 3) Provide performance data for year 2006: weaning rates, pregnancy rates, weaning weights