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<OL> <LI> Define on-farm dynamics of food borne pathogens with an emphasis on Salmonella and E. coli and antibiotic resistant phenotypes. A particular emphasis is to establish the genotypic and phenotypic diversity of Salmonella and E. coli on dairy production units, their interaction with the dairy host population, the relationship of the endemic dairy bacteria with human source bacteria, and control points to reduce the on-farm prevalence of significant Salmonella. <LI> Evaluate the economics of systems designed to minimize the use of antibiotics and decrease the occurrence of food borne pathogens. The focus of these studies will be on calf (beef, dairy, veal) and dairy production. Of interest is to evaluate nutrition and initial assessments of newly arrived animals as possible interventions. <LI> Evaluate the impact and utility of new technologies, e.g. oral antibody supplementation, colostrum supplements, mechanization, biological screening, novel feed supplements, and computer-assisted decision making on intensive and extensive management systems and the markets they serve. <LI> Describe the ecology of dairy waste systems (lagoons and manure packs) on the selection and maintenance of food borne pathogens. <LI> Evaluate modalities and needs for training of veterinarians and producers to understand the implications of new management systems and the public policy that endorses them.
NON-TECHNICAL SUMMARY: The management of animal production units contributes to problems associated with animal, environmental, and public health. The purpose of these studies is to evaluate on-farm interventions that contribute to improving animal, environmental and public health and enhance producer profitability.
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APPROACH: One: The initial focus of the studies is on clinical and non-clinical isolates of Salmonella and E. coli and their response to therapy. Genetic studies will focus on specific virulent and resistance genes on the virulence plasmid. The phenotypic studies will center on carbohydrate metabolism and antibiotic susceptibility. The complex of these attributes and isolate source will be modeled using clustering methods to develop familial relationships and compare between therapy groups. The second phase is to describe the relationship of Salmonella and E. coli clusters to the animal host and age dependency of the clusters. The third phase will describe the relationship between bovine and human isolates of Salmonella. The objective is to describe distances between isolates based on genetic and phenotypic attributes. The final phase is based upon on-farm studies focused on critical populations of Salmonella with human relevance. These studies will incorporate epidemiologic studies of risk for the presence of these pathogens on the dairy, identifying reservoirs for the bacteria, and identifying environmental survival of the pathogens. Two: The initial focus of these studies will be on calf production (beef, dairy, veal). The primary interest is to evaluate nutrition and initial assessments of newly arrived animals as interventions to increase the value of product, reduce the use of antibiotics, and decrease the prevalence of antibiotic resistance. A series of clinical trials will be established on demonstration farms to evaluate interventions with the outcomes being costs and benefits on health and the prevalence of antibiotic resistance in commensal bacteria. Three: These studies focus on calf and dairy production. A case control approach contrasting herds with organic or high quality markets compared with herds with conventional markets will be designed. The focus is to evaluate the impact and utility of new technologies on competitiveness and acceptability of the technologies to the markets they serve. Four: The first phase of these studies will evaluate the bacterial ecology of dairy lagoon systems. A cross-sectional study of herds will be conducted to assess the variability of lagoon designs, the functional aspects of water movement, the management of lagoon systems. The objective is to describe the attributes of lagoons on the prevalence of bacterial animal and public health pathogens. The second phase is to evaluate airborne transport of bacterial pathogens within and between dariy farms. A cross-sectional study of dairy farms will be conducted to assess the amount and dynamics of air-borne transport of bacteria. Five: The initial phase of this research is to evaluate the needs and skills required for veterinarians to address changing agricultural systems and policy. The approach is through an internet/mail survey of graduates from veterinary school and associated programs. The outcomes to be evaluated include understanding of policy changes, the significance of non-traditional veterinary skills to their practice, and the need for educational programs to address possible needs.
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