Science Page: Effects of gestation pens versus stalls and wet versus dry feed on air contaminants in swine production (Part 1)

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing part of a scientific paper from faculty in the School of Public Health at the University of Minnesota, regarding the effect of gestation pens versus group housing and dry versus wet feed on air contaminants. This week we are sharing the first half of the results, join us next week to read the second part.


  • Pollutant levels increased as ventilation rates decreased during the cold months.
  • Pen housing lead to higher levels of NH3, respirable dust, and endotoxin when compared to stalls.


Evolving production practices in the swine industry may alter the working environment. This research project characterized the influence of stall versus pen gestation housing on air contaminant concentrations.


Eight-hour time-weighted ammonia, hydrogen sulfide, respirable dust, respirable endotoxin, and carbon dioxide concentrations and temperature were measured
regularly at stationary locations throughout a year in a facility with parallel gestation stall and open pen housing. Hazard indices were calculated using ammonia,
hydrogen sulfide, and endotoxin concentrations and relevant occupational exposure limits.

air contaminant group housing versus stall


Due to reductions in ventilation rates as outdoor temperatures decreased, season affected pollutant levels more than other factors. Concentrations were greater during the
winter than summer (Figure 1). Ammonia, dust, and endotoxin were 25%, 43%, and 67% higher, respectively, on average, in the room with gestation pens than in the room with stalls. While individual contaminant concentrations were generally below regulatory limits, hazard index calculations suggest that the effects of combined exposures on respiratory health may pose a risk to farm workers. Additionally, elevated levels of respirable endotoxin and hydrogen sulfide were detected during power washing.


Ventilation changes in response to seasonal requirements influenced air contaminant concentrations more than production practices, especially housing type.

You can also read the full article on the journal’s website.

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