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Quantitative Herd-Level Evaluation of the Potential for a Commercially Available Vaccine to Effectively Control Salmonella in Dairy Cattle

Webb, Hattie; McCarthy, Rebecca; Loneragan, Guy; Farrow, Russell; Edrington, Thomas; Brashears, Mindy; Osterstock, Jason; Norby, Bo; Daniels, Angela
Texas A&M University
Texas Tech University
USDA - Agricultural Research Service
West Texas A&M University
Texas A&M AgriLife Research
Circle H Animal Health LLC
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Effective control of Salmonella in beef products is needed and pre-harvest intervention strategies are critical components of an integrated systems approach to ensure beef safety. Culled cows from the dairy industry contribute substantially to US the beef supply, especially ground beef products and have often been implicated in Salmonella-positive product. Therefore, pre-harvest strategies aimed at reducing the burden of Salmonella in these animals is of utmost concern. Conditionally licensed vaccines hold promise in their ability to increase the effective immunity of the treated animals against various pathogens including Salmonella. This research aids in the understanding of herd level factors that are responsible for the Salmonella burden.

1. To quantitatively determine whether a commercially available vaccine can effectively control burden of Salmonella on dairies;

2. To evaluate farm-level variables that explain a significant amount of variation in Salmonella shedding on dairies;

3. To partition unexplained variation in Salmonella shedding to within- and between- herd dynamics.

More information
Findings: Salmonella is ubiquitous throughout the study population and multiple serotypes previously identified in human outbreaks were identified. However, most isolates recovered were pan susceptible to a broad range of antibiotics. Additionally, a majority of the observed variation was within individual herds which in the future may aid in understanding herd-level drivers responsible for the current Salmonella burden.
Funding Source
Nat'l. Cattlemen's Beef Assoc.
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