Theses and Dissertations

Issuing Body

Mississippi State University


Wills, Robert W.

Committee Member

Jack, Sherman W.

Committee Member

Huston, Carla L.

Committee Member

Harvill, Jane L.

Committee Member

Bailey, R. Hartford

Other Advisors or Committee Members

Hubbard, Sue Ann

Date of Degree


Original embargo terms

MSU Only Indefinitely

Document Type

Dissertation - Campus Access Only


Veterinary Medical Science

Degree Name

Doctor of Philosophy


College of Veterinary Medicine


Department of Pathobiology and Population Medicine


Reducing the frequency of Salmonella in broiler flocks is important from both the standpoints of food safety consumer protection and industry viability. The goal of this dissertation is to provide a more complete identification, characterization and assessment of significance of the risk factors potentially associated with broiler flock Salmonella status as the flock progresses through sequential segments of the production continuum. The sequential segments of the continuum are: broiler breeders and hatchery, transportation from hatchery to grow-out farm, grow-out, transportation from farm to processing plant and processing. In this study broiler flocks were sampled through an entire grow-out production cycle, starting from the flock?s arrival from the hatchery to the grow-out farm, then, at the end of grow-out, upon arrival to the processing plant, and at the pre-chill and post-chill points of processing. Litter samples and drag swabs of the litter were collected in the grow-out house prior to placement and after the harvest of the flock. Epidemiological tools, questionnaires and checklists, were developed and utilized together with the company production records, soil, climatologic and other data to characterize potential risk factors of grow-out broiler flock Salmonella status. Regression modeling was used to investigate associations between the described risk factors and the sampled flock?s Salmonella status. Interrelationship of the flock and grow-out environment Salmonella status at the sequential production segments was studied as a risk factor. Models were built to describe the risk factors of Salmonella contamination of the litter and drag swabs collected in the grow-out house prior to placement of the birds. Following, models were built to identify the risk factors associated with broiler flock Salmonella status upon delivery from the hatchery to the farm and at the end of the grow-out.



Epidemiology||Risk factor analysis||Salmonella||Broiler||Food safety