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Objective 1: Characterization of host mechanisms associated with mastitis susceptibility and resistance. Missouri will contribute by investigating the relationship between Bovine Leukosis Virus (BLV) infection and chronic subclinical mastitis. In addition, we will be evaluating the influence of subclinical hypocalcemia on peripartum energy balance, post-partum disease, and subclinical mastitis.<p> Objective 2: Characterization and manipulation of virulence factors of mastitis pathogens for enhancing host defenses. Missouri will contribute by studying the influence of coagulase negative staphylococcal species and genotype on milk somatic cell count and chronicity of infection. <p>Objective 3: Assessment and application of new technologies that advance mastitis control, milk quality and dairy food safety. Missouri will contribute through ongoing clinical trials evaluating the efficacy of staphylococcal mastitis vaccines and treatment protocols for staphylococcal mastitis.
NON-TECHNICAL SUMMARY: Bovine mastitis is the most costly infectious disease currently affecting dairy cattle. While significant advances have been made in controlling some types of mastitis, the complex etiology of the disease and ongoing changes in dairy practices dictate that new and more effective methods for control and treatment be developed over time. Single site studies are often limited in terms of expertise and cattle numbers. A multi-State project provides advantages in terms of increased numbers of herds and cattle as well as multiple levels of expertise. The purpose of the NE 1028 project is to conduct collaborative projects which will lead to new information of value to the management of dairy cattle mastitis and thereby enhance the safety of dairy foods. Mastitis is an evolving disease syndrome as is the science which studies mastitis, and therefore continued research efforts are needed.
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APPROACH: <p>Objective 1: Characterization of host mechanisms associated with mastitis susceptibility and resistance. The 1st project will evaluate the relationship between BLV infection, persistent lymphocytosis, and the presence of chronic subclinical intramammary infections in dairy cattle and compare results with non-BLV infected cattle. The 2nd project will compare post-partum health parameters between cows which have subclinical hypocalcemia at calving and those which are normocalcemic at calving as determined by measurement of plasma ionized calcium concentrations. <p>Objective 2: Characterization and manipulation of virulence factors of mastitis pathogens for enhancing host defenses. A study is currently underway to evaluate coagulase negative staphylococcal intramammary infections in dairy cattle. Serial milk samples collected over a 16 month period from all quarters of all cows are being cultured for staphylococci. Coagulase negative staphylococci will be speciated and then fingerprinted using pulsed-field gel electrophoresis (PFGE). Chronicity of infection and milk somatic cell count will be compared between species and genotype to determine if there are differences in pathogenicity between species and genotypes within species. <p>Objective 3: Assessment and application of new technologies that advance mastitis control, milk quality and dairy food safety. We are currently evaluating the efficacy and humoral immune response of a commercially available staphylococcal mastitis bacterin. In addition we will continue to carry out clinical trials evaluating efficacy of treatment for staphylococcal mastitis.