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There are two main objectives of our research plan over the next five years: <OL> <LI> Continue to determine efficacy of antibacterial drugs as a therapy for clinical mastitis. Special emphasis will be given to severe clinical mastitis. Additionally, we will establish protocols that encourage prudent drug use in relation to pre-harvest food safety, reduce the risk of developing resistance of pathogens to antibacterial drugs, and practice sound pharmacokinetic and pharmacodynamic principles.<LI> We will develop and enhance the efficacy and technology of Gram-negative bacterins. Under this objective, there will be three foci: <UL> <LI> Apply novel management practices to try to maximize the efficacy of currently available vaccines. <LI> Develop new generation of core-antigen bacterins that will enhance cell mediated and humoral responses to immunization in dairy cattle. <LI> Determine factors (nutritional and infectious) that may alter the response of cattle to core-antigen immunization.
NON-TECHNICAL SUMMARY: Mastitis is a an important disease of dairy cattle, and therapy of mastitis is often unsuccessful Vaccination and immune enhancement strategies for mastitis are not successful This purpose of this project is to reduce losses form amstitis from better therapeutic intervention and enhancing the immune resistance of the cow to infection. Severe coliform mastitis continues to cause significant losses to dairy producers. Current vaccines offer limited protection for dairy catle. We have furthered our understanding of the immunological changes that occur from immunization with of currently available vaccines. Our research is attempting to improve methods to vaccinate dairy cattle to protect them from this disease. Severe coliform mastitis continues to cause significant losses to dairy producers. Current vaccines offer limited protection for dairy catle. We have furthered our understanding of the immunological changes that occur from immunization with of currently available vaccines. Our research is attempting to improve methods to vaccinate dairy cattle to protect them from this disease. Mastitis continues to cause significant losses to dairy producers. Current vaccines offer limited protection for dairy cattle. We have furthered our understanding of the immunological changes that occur from immunization with currently available vaccines. Our research is improving methods to vaccinate dairy cattle to protect them from this and other diseases.
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APPROACH: <BR> Objective 1 - Continue to determine efficacy of antibacterial drugs as a therapy for clinical mastitis. In conjunction with commercial dairies and private practitioners, we will continue to evaluate potential application of MIC antibiograms for designing mastitis therapy protocols. We will collect representative bacterial isolates from participating herds and establish an MIC data base through the services of the Diagnostic Center for Population and Animal Health, Microbiology laboratory. This information will be used to identify the best therapy protocols. Outcomes to be measured will include cull rates and mortality related to mastitis, days in the sick pen and amount of milk discarded following the clinical mastitis case, and incidence of recurring cases. <BR> <BR> Objective 2- Apply novel management practices to try to maximize the efficacy of currently available vaccines and develop new generation of core-antigen bacterins that will enhance cell mediated and humoral responses to immunization in dairy cattle. It is anticipated that different bacterin formulations will be tested in dairy cattle to determine 1) serum and milk IgG1 and IgG2 responses, and 2) the to promote T-cell maturation as indicated by proliferation and cytokine response to the bacterin antigen. Following this initial phase, potential candidates will be tested in cattle for safety and efficacy in reducing the severity of clinical coliform mastitis. Collaboration is also expected with Dr. Lorraine Sordillo, Meadowbrook Professor of Animal Health, Department of Large Animal Clinical Sciences. Determine factors (nutritional and infectious) that may alter the response of cattle to core-antigen immunization. Preliminary studies in conjunction with Dr, Sordillo have suggested that cows infected with Bovine Leukosis Virus (BLV) may have impaired responses to immunization, including core-antigen bacterins. One area of investigation that has received little attention is the potential impact of BLV status and altered immune function on vaccine efficacy. The overall goal of this project is to determine the impact of BLV status on J5 bacterin vaccine protocols. If we determine that BLV infection alters the ability of the bovine immune system to respond to vaccination, the implications for maintaining the health and well being of dairy cattle in the face of infectious challenge from mastitis pathogens, and potentially organisms that cause disease in other tissue systems, will be far-reaching. RJ Erskine has a part-appointment in cooperative extension, and thus regularly participates in outreach activities and learning progrmas. This opportunity, coupled with publications in peer-reviewed and industry-related journals, will be used to disseminate information gained from this research to the target audience.