The increasing public concerns to raise animals in better conditions are pushing the poultry sector progressively towards improving animal welfare in Canada and around the world. The estimation of gas, bioaerosols and dust emissions from animal buildings is necessary to evaluate and compare environmental and social impacts. Ventilation rate (VR) is a key parameter for the estimation of emissions. Godbout et al. 2022 pointed out that the CO2 balance was the most easily adaptable indirect technique. The aim of the present work is to adapt the CO2 balance method (CM) to evaluate the air change rate in livestock housing. Visits were made to different egg-producing farms in southern Quebec with three types of production systems (enriched cages (EC), cage-free systems (CFS), conventional eggs production (CP)). The results showed that the VR [m3 h-1 hen-1] in CP was by DM = 0.64, by CM = 0.72; in EC was by DM = 0.55, by CM = 0.64 and finally in CFS was by DM = 0.73, by CM = 1.05. For all systems, the indirect methods overestimate VR compared to direct measurements, being more significant in the EC and CFS systems. To increase the accuracy, an adaptation was carried out. The adaptation method was based on the CO2 balance determined by the CIGR 2002, where variations of variables such as the CO2 production rate of hens (PRCO2), the animal activity (AA) and the respiratory quotient of laying hens (RQ).

More than a half-million dry metric tons of sewage sludge are produced annually in Canada. Instead of landfilling or incinerating the sludge, it is increasingly processed into biosolids and applied to agricultural fields as organic fertilizer. We often assume that the greenhouse gas emissions (GHGs) resulting from this practice are net-negative, but this has not been well studied. To help address this research gap, we conducted field experiments at sites in Truro (NS), Montreal (QC), and Edmonton (AB). Sewage sludge was either anaerobically digested, composted, or alkaline stabilized. At each site, we applied the resulting biosolids alone or in combination with chemical fertilizer at rates commensurate with the nutrient requirements of the crop, according to a randomized complete block design with positive and negative controls. We measured GHGs (CO2, CH4, and N2O) from the field with both automated and manual flux chambers, and performed a carbon-footprint analysis to estimate related upstream GHGs. Soil and crop characteristics were measured to quantify agronomic impacts. Crop production was equivalent for all treatments except the negative (zero fertilizer) controls (P<0.05). Field emissions of GHGs were greatest from plots fertilized with digested biosolids (P<0.05). The plots amended with composted biosolids had the largest overall carbon footprint, including upstream GHGs, because of the large amount of material processed to supply the crop nitrogen requirements. These results provide region-specific data about GHGs from field-applied biosolids and will help improve Canada’s national GHG inventory as reported to the Intergovernmental Panel on Climate Change.

Alternative breeding methods have been suggested to allow animals to express their natural behaviors. In laying hen production, cage-free systems (aviaries) and enriched cages are alternatives to improving animal welfare. Compared to conventional and enriched cage systems, aviaries face challenges related to air quality. Airborne contaminants inside animal buildings are composed of gases and dust particles which can contain microorganisms, microbial metabolites, animal proteins, and other fragmented materials. Thus, the measure of gas and dust concentration as well as the estimation of their emissions from animal buildings is necessary to evaluate, compare and decrease environmental, human, and social impacts. Twenty-four poultry operations were visited to evaluate the air quality and collect data on building and management practices. Dust concentration was monitored with an optical particle counter. Gas concentration, airflow rate, temperature, and humidity were also measured by using a FTIR analyzer and a thermos anemometer with a hotwire probe. Results revealed that the average dust and NH3 concentrations were higher in aviaries than in enriched cages. However, other variables (in addition to the type of production system) can influence results and need to be considered. Gas emissions values were calculated, and these were more influenced by the other variables than the type of production system. It is suggested to improve strategies to decrease dust and NH3 concentration in most aviaries systems.

In Quebec, the agricultural sector is responsible for 10.6% of the total greenhouse gas (GHG) emissions, which are mainly from enteric fermentation (36.2%), soil management (32.8%) and manure management (26.3%). About 22% of GHG emitted from manure management in Canada are from swine production. Moreover, ammonia (NH3) is mainly emitted from the agricultural sector, as 65% of these emissions are from livestock productions. To reduce the GHG emissions from swine production, it is possible to adopt different strategies, whether in the building, at storage or during spreading, which are the main sources of emissions in the sector. In-barn strategies such as the separation of the solid and liquid fractions of slurry, the use of automatic feeders with a diet modification and the control of low temperature environment inside the rooms, can reduce of GHG and NH3 emissions. The main objective of this study was to evaluate GHG and NH3 emissions by comparing the above-mentioned strategies with the strategies commonly used in the Quebec swine industry. Experimental trials were carried out in the DC-102 laboratory at the experimental farm of IRDA (Deschambault, QC), comprising three experimental rooms with a fully slatted floor and a housing capacity of 14 pigs per room in fattening and finishing stages. Two tests repeated twice were carried for a period of 40 days each to evaluate the individual and combined impacts of the proposed strategies on GHG (N2O, CO2 and CH4) and NH3 emissions. The present results are under treatment and are expected to be completed in May 2023.