Feeding corn dried distillers grains with solubles (DDGS) to swine is becoming common in pork production. With feed being the primary cost in pork production and continued interest in quantifying and mitigating aerial emissions from animal feeding operations, it is important to understand the impacts of non-traditional dietary formulations on air emissions. Literature information is meager concerning the impact of feeding DDGS to swine on gaseous emissions, especially under long-term, field production conditions. Hence, the purpose of this study was to assess the impacts of including DDGS in animal diet on ammonia (NH3), hydrogen sulfide (H2S) and greenhouse gas (GHG) emissions from deep-pit swine wean-to-finish (5.5 – 118 kg) facilities in Iowa, the leading swine producing state in U.S. To attain the study objectives, two commercial, co-located wean-to-finish barns (2400/1200-head capacity at double/single stocking density) were monitored: one barn received a traditional corn-soybean meal diet (designated as Non-DDGS regimen), while the other received a diet that included 22% DDGS (designated as DDGS regimen). Gaseous concentrations and barn ventilation rate (VR) were monitored or determined semi-continuously throughout the study using a state-of-the-art mobile air emissions monitoring unit; and the corresponding emission rates (ER) were derived from the concentration and VR data. Two turns of wean-to-finish pig production were monitored for this study, covering the (14-month) period of December 2009 to January 2011, hence the effect of the season and manure accumulation in the pit. Market body weight of the pigs averaged 260 lbs. The daily and cumulative emissions are expressed on the basis of per barn, per pig, and per animal unit (AU, 500 kg live body weight). Emissions during both production period (i.e., with pigs present in the barns) and downtime (empty barns) were included in the emissions quantification.
Results of this extensive field study indicate that feeding 22% DDGS does not significantly affect the gaseous emissions (NH3, H2S, CO2, N2O and CH4) when compared to the Non-DDGS regimen in the deep-pit wean-to-finish swine facility. Cumulative emissions (mean ± SE), in lbs gas per pig marketed (at 255 lbs body weight), was 3.12±0.64 NH3, 0.156±0.086 H2S, 878±61 CO2 and 30.6±14.4 CH4 for the Non-DDGS regimen; and 3.30±0.01 NH3, 0.172±0.101 H2S, 741±50 CO2 and 19.8±4.64 CH4 for the DDGS regimen. On the basis of lbs gas emission per animal unit (AU, 1100 lbs live body weight) marketed, the values were 13.4±1.94 NH3, 0.66±0.33 H2S, 3777±33 CO2 and 128±54 CH4 for the Non-DDGS regimen; and 13.8±0.44 NH3, 0.70±0.40 H2S, 3093±117 CO2 and 82±17 CH4 for the DDGS regimen. The information should help filling the knowledge gap of GHG emissions and impact of DDGS on gaseous emissions from modern U.S. pork production.