2010 Annual Report
1a.Objectives (from AD-416)
The objective of this agreement is to build upon a long-term project designed to evaluate the impact of intervention strategies on Johne’s disease dynamics, milk and beef quality (particularly with respect to zoonotic bacterial pathogens), economics and sustainability through intensive longitudinal follow up of well-characterized research/demonstration dairy farms. Long-term goals are to validate intervention strategies to support best management practices (BMPs) and to optimize intervention and monitoring strategies given the constraints on time, labor and financial resources in modern dairy herds. In addition, a national resource bank (data and biological specimens on well-characterized animals) will be maintained for current and future monitoring and research on dairy cattle diseases. Emphasis will be on longitudinal data collection on endemic infectious diseases of public and animal health concern.
1b.Approach (from AD-416)
Pathogens are of increasing concern on dairy farms and in dairy products. The production of safe and wholesome food from U.S. farms requires control of the production process on the farm. Specific focus areas in this process are biosecurity, food safety and animal health. To be able to scientifically support regional process control programs there is a need for longitudinal research on commercial dairy farms throughout the United States. For several years, Cornell University, The Pennsylvania State University, The University of Vermont, and the University of Pennsylvania, which are all participants in the Regional Dairy Quality Management Alliance (RDQMA), have collaborated with the USDA’s Environmental Microbial Safety Laboratory to study the disease dynamics of endemic infectious diseases on three operating dairy farms. The goal is to identify sites that act as reservoirs for pathogenic microorganisms that affect animal health and/or decrease product quality because of their zoonotic nature. Serum, feces, bulk tank milk, and environmental samples (water, bird and rodent feces, feed, etc.) will be taken on the farm. In addition, tissue samples will be obtained from carcasses of culled animals. Samples will be distributed among the university and ARS researchers for analysis to determine the presence of Mycobacterium avium paratuberculosis (the causative agent of Johne’s disease in cattle) and for Salmonella enterica, Escherichia coli O157:H7 and other enteropathogenic forms of E. coli, and Listeria monocytogenes (human food-borne pathogens of concern in dairy products). This research is the first to attempt a comprehensive analysis of both Johne’s disease and food-borne pathogens on working dairy farms. We have gathered extensive baseline data for these organisms on three farms and have set the stage for investigation of the effect of interventions, in the form of BMPs, on animal health and product quality.
Milk, milk filter, environmental and fecal samples were collected on a regular basis from a dairy farm in Pennsylvania and analyzed for the presence of Mycobacterium avium subsp. paratuberculosis (MAP, the causative agent of Johne’s Disease in cattle) and the zoonotic food-borne pathogens Listeria monocytogenes, Salmonella enterica, and pathogenic forms of Escherichia coli. Through constant monitoring and aggressive culling Johne’s disease was eliminated on the farm accessed through this agreement; continued analysis confirms all animals remain free of MAP as determined by serological and microbiological assays. The continued study of a long-term colonization of dairy cows by Salmonella enterica captured a unique shift in the serotype infecting cows on this farm. A trial to determine if a commercially available Salmonella vaccine would affect the carriage of Salmonella bin cows was continued. Weekly milk samples from 3 farms were analyzed for common microbial milk quality indicators. Farm surveys were completed within required time and samples were obtained and distributed as required.
The ADODR has monitored activities associated with this project through participation in farm sampling events, and through frequent phone calls and emails. An annual meeting of all major participants in this project was held. In addition, discussions were held at the annual NEUSAHA meeting. ADODR reviewed SF 269A forms.