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Tufts OpenCourseware
Authors: Kathleen Merrigan, Ph.D., William Lockeretz, Ph.D.


  • Iowa State University Extension. Livestock Confinement Dust and Gases.
  • Iowa State University and The University of Iowa Study Group. Iowa Concentrated Animal Feeding Operations Air Quality Study. Final Report. Chapter 1, Executive Summary, and Chapter 7, Social and community impacts. 2002.
  • McEwen, S.A., and Fedorka-Gray, P.J. Antimicrobial use and resistance in animals. Clinical Infectious Diseases 34:Suppl 3. 2002.
  • Alliance for the Prudent Use of Antibiotics. The Need to Improve Antimicrobial Use in Agriculture. Executive Summary. 2002

Key Questions

Livestock Confinement Dust and Gases

  • What are the sources of health hazards to workers in confined animal operations?
  • What are the symptoms that indicate that the health of workers in confinement operations is adversely being affected?
  • Other than the pollutants themselves, what other factors influence worker health?
  • What are some of the management options that will enhance worker safety?

Iowa Concentrated Animal Feeding Operations Air Quality Study

  • What are the impacts of CAFOs on worker, environmental and community health?
  • Which pollutants from CAFOs should we be concerned about?
  • For which of the pollutants has a maximum residue level ( MRL) been set?
  • Do pollutants from CAFOs affect the workers and those in the surrounding community differently? If so, why?
  • Which federal agencies are concerned with regulating pollution from CAFOs?
  • What are the policy options suggested by the authors for regulating and mitigating pollutants from CAFOs?
  • At what source points do the authors suggest that pollutants from CAFOs be measured?
  • What is the significance of additive effects for setting up tolerance levels?
  • What is a manure management plan?
  • Does the Occupational Safety and Health Administration ( OSHA) have standards to protect CAFO workers from pollutants?
  • Are all CAFOs regulated by OSHA?
  • What is the difference between vertical integration and vertical coordination?
  • What is the potential of the suggested vertical coordination in reducing the adverse impacts of CAFOs?
  • Considering the Freedom to Farm Act of 1996, why doesn’t a shift in cropping pattern occur despite low market prices for corn and soybean?
  • What conditions are essential to promote alternative animal production systems?

Antimicrobial Use and Resistance in Animals

  • What are the different systems of antibiotic usage in animal production units?
  • What are the factors that a livestock producer might consider before using antibiotics?
  • Are growth promoting antimicrobials used in a) aquaculture, b) organic farming?
  • When is antibiotic usage in animal production a concern for human health? What is the process involved?
  • How has concern over usage of antibiotics in animal production shifted over time?
  • Which federal agency and act regulates the drugs available for treating animals being raised in confinement?
  • What framework is used to determine the safety of usage of antibiotics in animal production?
  • What conditions encourage producers to use antibiotics for subtherapeutic purposes?
  • What is the significance of Animal Medicinal Drug Use Clarification Act when one considers the use of antibiotics in animal production?
  • How have veterinarians and producer groups responded to the public’s concern over subtherapeutic antibiotic use in animal production?
  • Why do conflicting projections regarding the extent of antibiotic usage for subtherapeutic purposes exist? How can this problem be overcome?
  • How are some of the European countries, like Denmark and Sweden, managing the problem of subtherapeutic usage of antibiotics? What do their experiences reveal?
  • What are the implications of banning subtherapeutic usage of antibiotics?
  • What are the alternatives that can be tried instead of subtherapeutic usage of antibiotics?