Degree Type

Thesis

Date of Award

2019

Degree Name

Master of Science

Department

Agricultural and Biosystems Engineering

Major

Agricultural and Biosystems Engineering

First Advisor

Michelle L. Soupir

Abstract

Manure produced by animal feeding operations (AFOs) is commonly applied to surrounding agriculture fields as an agroeconomic practice to improve soil fertility and properly dispose of manure on-site. Antibiotics are utilized by AFOs to control, prevent, and treat disease in livestock animals. Manure from antibiotic treated livestock contains undigested active antibiotic metabolites that provide selective pressure and facilitates the spread of antibiotic resistance to the environment. This two year study monitors a wide range of antibiotic resistance genes ermB, ermF (macrolides), tetA, tetM, tetO, tetW (tetracyclines), sul1, sul2 (sulfonamides), aadA2 (aminoglycosides), vgaA, and vgaB (pleuroutilins) and total fecal indicator bacteria (FIB) (E. coli and enterococci) and tylosin and tetracycline resistant enterococci in catchment outlet waters from a highly agriculturalized watershed. Samples were collected at catchment outlets with areas ranging from 221 to 804 hectares, a scale in which comparisons can be made between areas with and without manure application. Results of the total watershed analysis show higher concentrations of FIB resistance indicators in the growing season (June-August) and higher ARG indicators in the pre-planting (March-May) and post-harvest (September-December) seasons. The manured catchment had significantly higher (p<0.05) percent tetracycline and tylosin resistant bacteria than the non-manured catchment in 2017. Average ermB and tetM concentrations above the limit of quantification (LOQ) from catchment outlet waters ranged from

Copyright Owner

Timothy Patrick Neher

Language

en

File Format

application/pdf

File Size

123 pages

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