Progress 03/15/07 to 09/30/09
Outputs
OUTPUTS: The described project has been completed as designed. Results of the completed study have been presented at various producer continuing education programs including the Mississippi Cattlemen's Association Annual Conference, Missouri Cattlemen's Association Annual Conference, Georgia Cattlemen's Association Annual Conference, and the National Cattleman's Beef Association 2009 Annual Conference. PARTICIPANTS: M. Daniel Givens, project director; Soren P. Rodning, co-project director; This project provided a research training opportunity to Callie L. Nunley who was involved as a graduate student in the conduct of this research. Other collaborators included M. Shonda D. Marley, Yijing Zhand, Andrew B. Eason, Paul H. Walz, Kay P. Riddell, Patricia K. Galik, and Bruce W. Brodersen. TARGET AUDIENCES: Veterinarians, cattle producers, vaccine manufacturers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Eighty crossbred beef heifers were randomly assigned to 1 of 4 treatment groups to evaluate the efficacy of vaccination in preventing the development of calves persistently infected with BVDV. Group 1 (n=11) served as non-vaccinated controls, while 3 groups were vaccinated with commercially available multivalent vaccines containing modified-live or inactivated BVDV at weaning, 28 d post-weaning, approximately one year of age, and 28 d later. Groups 2 (n=23) and 3 (n=23) were administered a modified-live BVDV vaccine, while Group 4 was administered an inactivated BVDV vaccine. Heifers were artificially inseminated (AI), after which two bulls were introduced. Pregnancy status and gestational age were assessed 61 d post-AI via transrectal ultrasound. Seventy heifers became pregnant (n=10 for Group 1; n=20 for Groups 2, 3, and 4). Three animals persistently infected with BVDV were commingled with the pregnant heifers in an isolated pasture for approximately 60 d (68 to 126 d post-AI). After BVDV exposure, viremias were detected in pregnant heifers from Group 1 (10/10), Group 3 (1/20), and Group 4 (10/20). No viremias were detected in Group 2 (0/20). Resulting calves were assessed for persistent infection using serum PCR, serum virus isolation, ear notch antigen capture-ELISA and immunohistochemistry. Persistently infected calves were only produced in Group 1 (10/10) and Group 4 (2/18). Results demonstrate that commercially available vaccines can provide effective fetal protection despite prolonged natural exposure to BVDV. However, viremias were detected in 11 vaccinated heifers after BVDV exposure and two vaccinated heifers gave birth to persistently infected calves, indicating the continued need for biosecurity and diagnostic surveillance in addition to vaccination to ensure effective BVDV control.
Publications
- Rodning SP, Marley MSD, Zhang Y, Eason AB, Nunley CL, Walz PH, Riddell KP, Galik PK, Brodersen BW, Givens MD. 2010. Comparison of three commercial vaccines for preventing persistent infection with bovine viral diarrhea virus. Theriogenology, doi:10.1016/j.theriogenology.2010.01.017
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: This project has resulted in a controlled research study involving 70 cows, 3 different commercially available vaccines for bovine viral diarrhea virus (BVDV), and challenge of vaccinated heifers by exposure to persistently infected cattle for 56 days duration. The results of this study have been shared at the 7th European Society for Veterinary Virology Pestivirus Symposium in Uppsala, Sweden (September 2008) as a platform presentation, at the Annual Conference of the American Association of Bovine Practitioner's in Charlotte, NC (September 2008) as a poster presentation, at the 4th BVDV Symposium in Phoenix, AZ (January 2009) as a poster presentation, and at the Alabama Food Animal Vaterinarian Conference in Columbiana, AL (February 2009) as a platform presentation. The project has facilitated consulting with commercial producers of cattle vaccines to ensure the efficacy of available products. PARTICIPANTS: M. Daniel Givens, project director Soren P. Rodning, co-project director TARGET AUDIENCES: Veterinarians, cattle producers, vaccine manufacturers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This project resulted in the knowledge that (a) 4 doses of modified-live BVDV vaccine provided 100% protection against fetal infection of calves, (b) 4 doses of killed BVDV vaccine provided 89% protection against fetal infection of calves, and (c) lack of vaccination resulted in 100% fetal infection of calves. Viremia was prevented in only 50% of vaccinates receiving a killed viral vaccine compared to 95% and 100% of vaccinates receiving modified-live BVDV vaccine. Virus was detectable in nasal swabs of calves only when calves had not yet absorbed colostral antibodies. The study also demonstrated that some modified-live vaccines exhibit a greater negative impact on average daily gain immediately after vaccination. This may be economically important if ownership changes within a few weeks of vaccination. However, compensatory gain eventually neutralizes differences in average daily gain indicating that this effect is less critical if ownership is retained.
Publications
- Rodning SP, Zhang Y, Eason AB, Marley MSD, Nunley CL, Walz PH, Riddell KP, Galik PK, Brodersen BW, Givens MD. Efficacy of various vaccination protocols in preventing persistent infection of calves with bovine viral diarrhea virus. Proceedings and poster presentation (#4) at the Fourth U.S. BVDV Symposium, Phoenix, Arizona, January, 2009.
- Rodning SP, Givens MD, Zhang Y, Marley MSD, Nunley CL, Walz PH, Riddell KP, Galik PK. Assessing the epidemiologic impact of vaccination for bovine viral diarrhea virus. Proceedings and poster presentation at the American Association of Bovine Practitioners 2008 Annual Conference in Charlotte, NC, September 2008.
- Rodning SP, Givens MD, Zhang Y, Marley MSD, Nunley CL, Walz PH, Riddell KP, Galik PK, Eason AB. Evaluating the efficacy of vaccination for bovine viral diarrhea virus. Platform presentation and proceedings p. 102 of the 7th ESVV Pestivirus Symposium in Uppsala, Sweden, September 2008.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Preliminary results of this project have been shared in presentations at the Fort Dodge Animal Health Food Animal Symposium at Auburn, AL in January 2008, the Pfizer Veterinary Symposium at Opelika, AL in December 2007 and the 21st Annual South Carolina Large Animal Medicine Short Course at Columbia, SC in November 2007.
PARTICIPANTS: Participants of this project have included Givens MD, Rodning SP, Walz PH, and Marley MSD. This project has facilitated the research training of 2 undergraduate students and 2 graduate student.
TARGET AUDIENCES: The target audience for dissemination of research results includes cattle producers, veterinarians, biologics manufacturers and regulatory officials.
Impacts
Preliminary results of this project indicate that the stimulation of humoral immunity can be associated with a decrease in growth rate. While commercially available vaccines to immunize cattle for bovine viral diarrhea virus vary in ability to stimulate humoral immunity and impact growth rate, future results will characterize the resulting protection afforded by immunization with these various products when animals are challenged under field condtions. Obviously, preference should be given to using vaccines that minimize temporary impairment of growth rates while maximizing protection afforded under field conditions.
Publications
- No publications reported this period
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