Year 1

2019 - 2020 Year 1 Update

Air quality issues in conventional livestock barns affect animal welfare and put workers at an increased risk of suffering from infectious and non-infectious respiratory diseases. Livestock buildings that employ features to enhance animal welfare such as increased animal activities (freedom of movement, natural behaviours) and the addition of bedding materials may result in worse air quality than conventional barns without these features. This research project will compare the air quality of conventional and enhanced housing systems in poultry, dairy and pig operations. Technologies and engineering practices such as oil sprinkling and bedding management techniques will be evaluated for implementation in Canadian next-generation livestock buildings (enhanced animal housing systems).

In Year 1, Activity 4 was able to analyze the technical and economical requirements of commercial-scale implementation of in-floor heating in combination with the sprinkling of an acid emulsion on the litter in livestock facilities. This combination strategy was implemented in a commercial poultry operation (aviary) in Québec. While the strategy still needs to be optimized, the preliminary results are proof of concept and provide an estimate for the cost of implementing these technologies for improving air quality in alternative housing systems.

Data from the scientific literature and from other ongoing projects are in the process of being compiled to serve as reference values for air quality measurements inside conventional housing environments in poultry, pig and dairy operations. Reference values include those for the concentrations of total dust, PM10, PM2.5, endotoxins, gas emissions (CO2, CH4, N2O and NH3), human pathogens, and antibiotic resistance genes.

Next steps involve visits to various types of animal production facilities including two types of poultry operations (laying hens, conventional and enriched cages), dairy farms, and pig buildings to evaluate the air quality and collect data on building and manure management practices. In total, 40 operations will be visited, 20 in Eastern and 20 in Western Canada, including 8 dairy farms, 6 pig buildings and 6 poultry operations divided equally between conventional and buildings with alternative housing systems. Producers and workers will be interviewed to determine the most popular and efficient airborne contaminant reduction strategies to improve air quality in livestock buildings.

The Fédération des producteurs d’oeufs du Québec (FPOQ), the provincial organization representing egg farmers, helped to recruit egg producers to participate in the project. Currently, all poultry operations required for the study are now recruited.  

Year 2

2020 - 2021 Year 2 Update

During Year 2, the air quality in several poultry operations (laying hens) adopting alternative housing practices in Quebec was compared with air quality in conventional farms. Preliminary results of this evaluation show significant differences in ammonia and dust concentrations between the two different facilities. The design of the building, the ventilation system, and the manure management system were are variables that affected the dust concentrations and ammonia emissions found in both poultry operations.

Currently available technologies and strategies for reducing dust concentrations such as oil sprinkling and bedding management were evaluated on an experimental scale during Year 2. Oil-emulsion sprinkling combined with litter absorbent or a floor heating system was efficient at reducing aerosolized dust particle matter (PM) concentrations for respirable and fine particles (PM1, PM2.5, and PM4). It is important to note that respirable PM particles (PM4) can reach the lower respiratory tract of humans including the alveoli where PM particles may enter into the bloodstream through the alveoli walls. Oil-emulsion sprinkling-based strategies reduced more than 90% of PM concentrations without disrupting the laying hens’ natural behaviours and the performance of the aviary. Recent results demonstrated that it is possible to improve air quality in cage-free eggs production systems by the implementation of strategies such as oil sprinkling. These practices will be adapted and evaluated in the next year of the project to reveal technical-economic feasibility.


Evaluation of air quality in 12 poultry operations (laying hens) enabled the research team to collect data and to compare conventional and alternative housing systems. The number of laying hens per barn visited was between 14,000 and 35,000 birds. Ammonia concentrations were between 2 to 15 ppm but, in some barns exceeded 20 ppm. Measurements of greenhouse gas concentrations (carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) were recorded and revealed differences between barns except for N2O. Real-time monitoring in the 12 poultry operations demonstrated higher concentrations of dust particles in aviaries compared to barns with conventional or enriched cages, and alternative housing systems.

On-site visits carried out at different poultry operations including cage-free laying hens housing systems demonstrated that these types of animal housing environments allow hens to display a broader range of natural behaviours such as perching, dust bathing, foraging, scratching, kneeling, ruffling feathers, and pecking activities. However, from preliminary results, air quality in these housing systems is lower compared to systems with enriched or conventional cages. These findings indicate the need for techniques and strategies to reduce ammonia and dust and their implementation in commercial buildings using cage-free housing systems for laying hens.

Additional preliminary results from experimental aviaries have revealed the effectiveness of heating floors and sprinkling of an emulsion, a combination of water, oil and acid, on bedding litter to diminish airborne contaminants. Similarly, trials conducted in a commercial aviary showed the feasibility of implementing heating floors and sprinkling of an oil emulsion for the reduction of airborne contaminants. However, the efficacy of the strategy for use in improving air quality needs to be evaluated over an entire production cycle from start to finish to avoid the influence of accumulated dust re-aerosolization. Further evaluations of this strategy will then be done in two commercial aviaries in Year 3 in Quebec.

During the summer of 2020, measurements of greenhouse gases and ammonia were carried out on an experimental dairy farm in Deschambault, Quebec. The experiment included the evaluation of gas emissions at five locations for nine weeks. The locations were: two cow stalls (control), one indoor exercise pen, and two outsides exercise locations. Floor emissions were estimated to evaluate and compare the environmental impact of dedicated exercise zones. During Year 3, the impact of the implementation of airborne contaminant reduction techniques to improve air quality in the experimental barns will be evaluated.

Year 3

2021 - 2022 Year 3 Update

Dairy Farms

Stalling methods in dairy barns are an area targeted to improve animal welfare while maintaining the efficiency of the production system. The increased movement of dairy cows in barns is likely to cause more particles to become aerosolized and therefore increase the health risks associated with the barns. Thus, despite being beneficial for animal welfare, this movement could result in an increase in bioaerosols and respiratory diseases among workers. During Year 3, six dairy farms were visited (3 tie stalls, 3 free stalls). Up to now, no significant difference was observed for total bacteria or for dust fractions. However, ten other dairy farms still have to be visited during the Year 4 of the research project and analysis of samples from the 6 visited dairy farms for other air quality indicators is still ongoing.

Egg Production

In year 3, the comparison of air quality in conventional and alternative laying hen production systems was completed. A total of eighteen laying hen poultry operations (6 conventional, 6 enriched cages and 6 aviary systems) were visited. Samplings were carried out in the fall and winter of 2020 and 2021. It was observed that concentrations of ammonia (NH3), airborne dust, and bioaerosols were generally more important in aviaries than in facilities with cages (conventional or enriched). Mold is the only exception as similar values were found for all the types of housing. In aviary systems, air quality is affected due to an increase in animal activity and bedding material addition.

Pig Farms

Group housing in pig production has been suggested to allow the animals to express normal activity and behavior. However, in comparison to housing sows in individual crates, sows in group housing have more nose-to-nose contact as well as more oral contact with feces and urine. These factors could contribute to higher or faster transmission of pathogens. During Year 3, several criteria to compare air quality in sows gestation production systems were defined in collaboration with the Saskatchewan team members. At the same time, protocols for accurate assessment and monitoring of air quality from pig buildings with mechanical ventilation were developed. Samplings will be carried out during Year 4 to compare six facilities using individual crates with 6 group housing systems.

Year 4

2022 - 2023 Year 4 Update

Year 5

2023 - 2024 Year 5 Update



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