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The research goal of this proposal is to generate fundamental knowledge about non-aureus staphylococci, the most prevalent pathogens causing intramammary infections among dairy animals globally. Better understanding the non-aureus staphylococci (NAS) causing mammary gland infections can lead to more effective prevention and control measures of mastitis on dairy farms. Mitigating the effect of NAS mastitis (the leading contributor to bulk tank milk somatic cell count on farms with good milk quality) will help dairy producers achieve quality premiums for their product, thereby increasing their profitability.Research objective 1: a) Describe infection dynamics and b) identify potential risk factors for intramammary infections due to the non-aureus staphylococci (as a group) on 10 organic dairy herds in Vermont. Research objective 2: a) Describe species diversity of non-aureus staphylococci causing intramammary infections on 10 organic dairy herds in Vermont, b) compare species-specific effect on quarter-milk somatic cell count, and c) identify potential risk factors explaining diversity of NAS species causing intramammary infections.Research objective 3: a) Identify if distinct strain types of S. chromogenes (the most common species of NAS identified) causing persistent intramammary infections will be associated with intramammary infections where quarter somatic cell count (SCC) is consistently elevated (HIGH SCC phenotype), vs. intramammary infections where quarter somatic cell count stays consistently low (LOW SCC phenotype) and b) if strain types of S. chromogenes from the HIGH SCC phenotype are more likely to carry genes encoding virulence factors as determined by whole-genome sequencing. The predoctoral fellowship training goal for this project is to become an expert in mastitis and veterinary epidemiology, a career path that ultimately seeks to increase dairy production by improving overall animal health and performance. During the 2 years of the AFRI NIFA predoctoral fellowship, I will achieve this through the following training objectives:Training objective 1: Prepare at least 2 scientific manuscripts from my research.Training objective 2: Expand my professional networks and career opportunities by connecting with members of my advisory board, who have with careers available to me as a future DVM/PhD (researcher at a renowned veterinary college, extension/outreach and animal health industry professional). Training objective 3: Strengthen networking and communication skills through conference and seminar presentations by presenting twice at the Mastitis Research Workers Annual conference, attending twice and presenting once at the National Mastitis Council Annual Meeting, and presenting once at the AFRI NIFA Fellows Project Directors' meeting while attending the Conference of Research Workers in Animal Disease.Training objective 4: Gain training in veterinary epidemiology through curricular activities outside UVM, including short courses by experts in the field on essential topics for epidemiological research ("Epi on the Island," Centre for Veterinary Epidemiological Research, U. PEI), a short course by experts in the field on essential topics for epidemiological research (handling bias in observational studies, multivariate and survival analysis), and online open courses from the National Mastitis Council (focused on mastitis epidemiology, diagnostics, mastitis control and milk quality).Training objective 5: Develop mentorship and leadership skills through training and overseeing undergraduate students in laboratory research and leading a class (in concert with my primary mentor) for undergraduates who may also be interested in completing the online course from the National Mastitis Council.

Jeffrey, C. E.
University of Vermont
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