A study assessed the effectiveness of oil sprinkling, low-protein diet, a high level of cleaning and manure pH manipulation in reducing ammonia (NH3) and respirable dust concentration in swine facilities.

At Prairie Swine Centre, six grow-finish rooms were used with two control and four experimental rooms, each employing one of the measures being studied.

Click here for figure 1

Every three weeks, worker exposure to NH3 and respirable dust was assessed by outfitting three workers with gas monitors and personal dust samplers over a two-day shift. Two workers were assigned to work in the experimental room, while the third worker was assigned in the control rooms. Each worker was assigned a logbook to document their activities during their shift while wearing the personal monitoring gear. Following exposure, rooms were sampled over 24 hours for NH3 levels and over 48 hours for dust concentrations.

Results of ammonia and dust levels are average measurements obtained over four sampling events in each of the two, 16-week trials.

Ammonia levels in rooms with manure pH manipulation, high levels of cleanliness and feeding a low-protein diet, were substantially lower than in the control rooms.

Readings from the commercial gas monitoring devices were considerably higher than levels from the standard NIOSH (National Institute for Occupational Safety and Health) method. But all rooms were below the threshold limit value of 25 ppm ammonia.

For the dust levels, only spraying of canola oil showed the potential to reduce dust concentration as shown in Figure 2. But all methods reduced dust levels to some extent.

In terms of respirable dust measurements, concentrations obtained from personal sampling were much higher than from area sampling, which could be due to different sampling durations. Area sampling was conducted over 48 hours, while personal sampling was done in a much shorter period.

Average daily gain of pigs in all rooms was fairly similar, while mortality rates were higher in the control rooms.

Control procedures showed potential to reduce ammonia concentrations. But only the spraying of canola oil showed the potential to reduce respirable dust concentration.

Researcher: Bernardo Predicala, University of Saskatchewan at Saskatoon. For more information, contact Predicala by phone (306) 667-7444, fax (306) 955-2510 or e-mail bernardo.predicala@usask.ca.