Identified factors and predicted unidentified-factors affecting ammonia emissions from a swine building

Large variabilities in ammonia (NH₃) released from animal manure and emitted from different livestock buildings were frequently reported, but the factors influencing the emissions were not sufficiently investigated. In this paper, continuously monitored data of NH₃ emissions and other relevant environmental variables under controlled conditions in a 12-room experimental swine building for a 155-d complete wean-to-finish cycle were studied. Measurement data mining was conducted at both spatial and temporal dimensions using panel data analysis with heterogeneous time trends. The pig diet, total pig weight, and the pit air temperature were identified as the major influencing factors for the variabilities by using multivariate linear regression. Two unidentified factors that imposed substantial influences on the NH₃ emission variabilities were predicted. They were most possibly related to variations in microenvironment and microbial activity inside the manure in the pit. The results suggest necessary future research to identify physical properties of the new NH₃ emissions factors in microbiological and biochemical processes.

Assessment of Interventions to Improve Air Quality in a Livestock Building

This study examined the effectiveness of engineering controls to reduce contaminant concentrations in a swine farrowing room during winter in the U.S. Midwest. Over two winters, changes in air quality were evaluated following installation of a 1700 m3 h-1 (1000 cfm) recirculating ventilation system to provide 5.4 air exchanges per hour. This system incorporated one of two readily available dust control systems, one based on filtration and the other on cyclonic treatment. A second treatment evaluated reductions in carbon dioxide (CO2) associated with replacement of standard, unvented gas-fired heaters with new vented heaters, installed between the two winter test periods. The concentrations of carbon monoxide and hydrogen sulfide were negligible in the test room. Although concentrations of ammonia increased over each winter test period, the increase was unrelated to increased air movement from the new recirculating ventilation system. The dust concentrations were significantly reduced by the ventilation system for both inhalable dust (23% to 44% with filtration, 33% with cyclone) and respirable dust (32% with filtration, 20% with cyclone), significant (p 0.024) for all except respirable dust using the cyclone (p = 0.141). The filtration unit is recommended to improve livestock building air quality because it was more effective than the cyclone unit at reducing respirable dust. Carbon dioxide concentrations were significantly lower with vented heaters (mean = 1400 ppm, SD = 330 ppm) compared to unvented heaters (mean = 2480 ppm, SD = 160 ppm). A 940 ppm reduction in CO2 was attributed to the use of the vented heater, after accounting for differences in outdoor temperatures and animal housing over both test periods. The benefits of readily available technology to significantly reduce concentrations of dust and CO2 demonstrates useful control options to improve air quality in swine buildings.

Mitigation of ammonia emissions from pig production using reduced dietary crude protein with amino acid supplementation

To mitigate ammonia (NH₃) emissions from pig production and understand dynamic emission profiles, reduced dietary crude protein (CP) with amino acid supplementation was studied with 720 pigs in a 12-room research building for 155days that covered from weaned to finishing stages. The pigs were divided into three 4-room groups and fed with 2.1-3.8% reduced CP (T₁), 4.4-7.8% reduced CP (T₂), and standard (control) diets, respectively. Compared with the control group, T₁ and T₂ decreased manure volumes and manure NH₄⁺-N concentrations. Group-mean NH₃ emission from the control group was 68.9gd^-1AU^-1 (AU=500kg live mass). Emissions from T₁ (46.7gd^-1AU^-1) and T₂ (29.8gd^-1AU^-1) were reduced by 33.0% and 57.2% (p<0.05), respectively. Dynamic peak NH₃ emissions appeared during the third nursery phase for T₁ and T₂, but delayed to the first grower phase for the control group.

Presence of animal feeding operations and community socioeconomic factors impact salmonellosis incidence rates: An ecological analysis using data from the Foodborne Diseases Active Surveillance Network (FoodNet), 2004-2010

Nontyphoidal Salmonella spp. are a leading cause of foodborne illness. Risk factors for salmonellosis include the consumption of contaminated chicken, eggs, pork and beef. Agricultural, environmental and socioeconomic factors also have been associated with rates of Salmonella infection. However, to our knowledge, these factors have not been modeled together at the community-level to improve our understanding of whether rates of salmonellosis are variable across communities defined by differing factors. To address this knowledge gap, we obtained data on culture-confirmed Salmonella Typhimurium, S. Enteritidis, S. Newport and S. Javiana cases (2004-2010; n=14,297) from the Foodborne Diseases Active Surveillance Network (FoodNet), and socioeconomic, environmental and agricultural data from the 2010 Census of Population and Housing, the 2011 American Community Survey, and the 2007 U.S. Census of Agriculture. We linked data by zip code and derived incidence rate ratios using negative binomial regressions. Multiple community-level factors were associated with salmonellosis rates; however, our findings varied by state. For example, in Georgia (Incidence Rate Ratio (IRR)=1.01; 95% Confidence Interval (CI)=1.005-1.015) Maryland (IRR=1.01; 95% CI=1.003-1.015) and Tennessee (IRR=1.01; 95% CI=1.002-1.012), zip codes characterized by greater rurality had higher rates of S. Newport infections. The presence of broiler chicken operations, dairy operations and cattle operations in a zip code also was associated with significantly higher rates of infection with at least one serotype in states that are leading producers of these animal products. For instance, in Georgia and Tennessee, rates of S. Enteritidis infection were 48% (IRR=1.48; 95% CI=1.12-1.95) and 46% (IRR=1.46; 95% CI=1.17-1.81) higher in zip codes with broiler chicken operations compared to those without these operations. In Maryland, New Mexico and Tennessee, higher poverty levels in zip codes were associated with higher rates of infection with one or more Salmonella serotypes. In Georgia and Tennessee, zip codes with higher percentages of the population composed of African Americans had significantly higher rates of infection with one or more Salmonella serotypes. In summary, our findings show that community-level agricultural, environmental and socioeconomic factors may be important with regard to rates of infection with Salmonella Typhimurium, Enteritidis, Newport and Javiana.

Impact of environmental policies on the adoption of manure management practices in the Chesapeake Bay watershed

Pollution in the Chesapeake Bay is a problem and has been a focus of federal and state initiatives to reduce nutrient pollution from agriculture and other sources since 1983. In 2010 EPA established a TMDL for the watershed. Producers may voluntarily respond to intense and focused policy scrutiny by adopting best management practices. A detailed analysis of water quality best management practices by animal feeding operations inside and outside the watershed yield insight into this relationship. Our findings support the hypothesis that farmers will adopt water quality measures if links are made clear and there is an expectation of future regulations.