Timothy A. Shepherd

Environmental assessment of three egg production systems--Part I: Monitoring system and indoor air quality.

To comprehensively assess conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as the Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern United States over two single-cycle production flocks. The housing systems studied include a conventional cage house (200,000 hen capacity), an aviary house (50,000 hen capacity), and an enriched colony house (50,000 hen capacity). As an integral part of the CSES project, continual environmental monitoring over a 27-month period described in this paper quantifies indoor gaseous and particulate matter concentrations, thermal environment, and building ventilation rate of each house. Results showed that similar indoor thermal environments in all three houses were maintained through ventilation management and environmental control. Gaseous and particulate matter concentrations of the enriched colony house were comparable with those of the conventional cage house. In comparison, the aviary house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher ammonia levels) and hens’ activities (higher particulate matter levels) in it. Specifically, daily mean indoor ammonia concentrations had the 95% confidence interval values of 3.8 to 4.2 (overall mean of 4.0) ppm for the conventional cage house; 6.2 to 7.2 (overall mean of 6.7) ppm for the aviary house; and 2.7 to 3.0 (overall mean of 2.8) ppm for the enriched colony house. The 95% confidence interval (overall mean) values of daily mean indoor carbon dioxide concentrations were 1997 to 2170 (2083) ppm for the conventional cage house, 2367 to 2582 (2475) ppm for the aviary house, and 2124 to 2309 (2216) ppm for the enriched colony house. Daily mean indoor methane concentrations were similar for all three houses, with 95% confidence interval values of 11.1 to 11.9 (overall mean of 11.5) ppm. The 95% confidence interval values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg/m3, were, respectively, 0.57 to 0.61 (0.59) and 0.033 to 0.037 (0.035) for the conventional cage house, 3.61 to 4.29 (3.95) and 0.374 to 0.446 (0.410) for the aviary house, and 0.42 to 0.46 (0.44) and 0.054 to 0.059 (0.056) for the enriched colony house. Investigation of mitigation practices to improve indoor air quality of the litter-floor aviary housing system is warranted.

Environmental assessment of three egg production systems — Part II. Ammonia, greenhouse gas, and particulate matter emissions

As an integral part of the Coalition for Sustainable Egg Supply (CSES) Project, this study simultaneously monitored air emissions of 3 commercially operated egg production systems at the house level and associated manure storage over 2 single-cycle flocks (18 to 78 wk of age). The 3 housing systems were 1) a conventional cage house (CC) with a 200,000-hen capacity (6 hens in a cage at a stocking density of 516 cm2/hen), 2) an enriched colony house (EC) with a 50,000-hen capacity (60 hens per colony at a stocking density of 752 cm2/hen), and 3) an aviary house (AV) with a 50,000-hen capacity (at a stocking density of 1253 to 1257 cm2/hen). The 3 hen houses were located on the same farm and were populated with Lohmann white hens of the same age. Indoor environment and house-level gaseous (ammonia [NH3] and greenhouse gasses [GHG], including carbon dioxide [CO2], methane [CH4], and nitrous oxide [N2O]) and particulate matter (PM10, PM2.5) emissions were monitored continually. Gaseous emissions from the respective manure storage of each housing system were also monitored. Emission rates (ERs) are expressed as emission quantities per hen, per animal unit (AU, 500 kg live BW), and per kilogram of egg output. House-level NH3 ER (g/hen/d) of EC (0.054) was significantly lower than that of CC (0.082) or AV (0.112) (P < 0.05). The house-level CO2 ER (g/hen/d) was lower for CC (68.3) than for EC and AV (74.4 and 74.0, respectively), and the CH4 ER (g/hen/d) was similar for all 3 houses (0.07 to 0.08). The house-level PM ER (mg/hen/d), essentially representing the farm-level PM ER, was significantly higher for AV (PM10 100.3 and PM2.5 8.8) than for CC (PM10 15.7 and PM2.5 0.9) or EC (PM10 15.6 and PM2.5 1.7) (P < 0.05). The farm-level (house plus manure storage) NH3 ER (g/hen/d) was significantly lower for EC (0.16) than for CC (0.29) or AV (0.30) (P < 0.05). As expected, the magnitudes of GHG emissions were rather small for all 3 production systems. Data from this study enable comparative assessment of conventional vs. alternative hen housing systems regarding air emissions and enhance the U.S. national air emissions inventory for farm animal operations.

Comparative evaluation of three egg production systems: Housing characteristics and management practices

This paper is an integral part of the special publication series that arose from the multidisciplinary and multi-institutional project of the Coalition for Sustainable Egg Supply (CSES). The CSES project involves 3 housing systems for egg production at the same research farm site in the Midwest, USA, namely, a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. The CC house (141.4 m L × 26.6 m W × 6.1 m H) had a nominal capacity of 200,000 hens (6 hens in a cage at a stocking density of 516 cm2/hen), and the cages were arranged in 10 rows, 8 tiers per cage row, with a perforated aisle walkway at 4-tier height. The AV house (154.2 m L × 21.3 m W × 3.0 m H) and the EC house (154.2 m L × 13.7 m W × 4.0 m H) each had a nominal capacity of 50,000 hens. The AV house had 6 rows of aviary colonies, and the EC house had 5 rows of 4-tier enriched colonies containing perches, nestbox, and scratch pads (60 hens per colony at a stocking density of 752 cm2/hen). The overarching goal of the CSES project, as stated in the opening article of this series, was to comprehensively evaluate the 3 egg production systems from the standpoints of animal behavior and well-being, environmental impact, egg safety and quality, food affordability, and worker health. So that all the area-specific papers would not have to repeat a detailed description of the production systems and the management practices, this paper is written to provide such a description and to be used as a common reference for the companion papers.

Impact of commercial housing systems and nutrient and energy intake on laying hen performance and egg quality parameters

The US egg industry is exploring alternative housing systems for laying hens. However, limited published research related to cage-free aviary systems and enriched colony cages exists related to production, egg quality, and hen nutrition. The laying hens nutritional requirements and resulting productivity are well established with the conventional cage system, but diminutive research is available in regards to alternative housing systems. The restrictions exist with limited availability of alternative housing systems in research settings and the considerable expense for increased bird numbers in a replicate due to alternative housing system design. Therefore, the objective of the current study was to evaluate the impact of nutrient and energy intake on production and egg quality parameters from laying hens housed at a commercial facility. Lohmann LSL laying hens were housed in three systems: enriched colony cage, cage-free aviary, and conventional cage at a single commercial facility. Daily production records were collected along with dietary changes during 15 production periods (28-d each). Eggs were analyzed for shell strength, shell thickness, Haugh unit, vitelline membrane properties, and egg solids each period. An analysis of covariance (ANCOVA) coupled with a principal components analysis (PCA) approach was utilized to assess the impact of nutritional changes on production parameters and monitored egg quality factors. The traits of hen-day production and mortality had a response only in the PCA 2 direction. This finds that as house temperature and Met intake increases, there is an inflection point at which hen-day egg production is negatively effected. Dietary changes more directly influenced shell parameters, vitelline membrane parameters, and egg total solids as opposed to laying hen housing system. Therefore, further research needs to be conducted in controlled research settings on laying hen nutrient and energy intake in the alternative housing systems and resulting impact on egg quality measures.

Development and Testing of a Fan Monitoring System Using Induction Operated Current Switches

Emissions of gaseous compounds and particulate matter are the product of the pollutant concentrations and air exhausted from the fans of mechanically ventilated animal confinement buildings. Direct methods of monitoring exhaust fan operation (i.e., mercury tilt, limit or whisker, and vibration switches) have been reported to have limitations due to mechanical failure and/or the effect of the environment (dust, wind, moisture). Another method involves monitoring the control relay status at the fan system control box. A problem could occur at the fan but not in the signal at the control box, thereby giving a false operational signal. The objective of this project was to find a more reliable method of monitoring fan operation status. This paper describes the development, lab testing, and use of a fan monitoring system based on induction operated current switches (ICS). ICSs are unaffected by the environment and can provide direct measurement of real-time fan operational status by sensing AC current. A laboratory test of the ICS was performed to simulate a fan off/on duty cycle in a two-year emissions study; no ICS failure was recorded. The Southeastern Broiler Gaseous and Particulate Matter Emission study led by Iowa State University has been using 28 ICSs for over 190 days without a failure. At a unit cost as low as

Development of a Bench-Scale Air Sparged Continuous Flow Reactor for Struvite Precipitation from Two Different Liquid Swine Manure Storage Systems

19.50 this method offers a reliable, accurate, and economical way of measuring the real-time operational status of ventilation fans – a critical component of any air emissions monitoring in a mechanically ventilated confinement system.

Technical Note: Development and Testing of an Induction-Operated Current Switch for Monitoring Fan Operation

Forced precipitation of struvite (MgNH4PO4 . 6H2O) can reduce dissolved reactive phosphorus (DRP) in swine manure slurries. Optimization of this process requires that the swine manure slurry pH be increased, that magnesium be added, and that sufficient reaction time be allowed for struvite precipitation. To gather data that could be used for a full-scale continuous-flow struvite precipitation reactor, a bench-scale (14-L) continuous flow reactor was designed, constructed, and tested. The bench-scale reactor used air sparging for both pH adjustment and mixing, used a peristaltic pump to continuously inject magnesium chloride (MgCl2 . 6H2O), and was operated at a 10-min hydraulic retention time. The bench-scale system provided a 95% reduction of DRP in swine manure slurry collected from a concrete storage tank with a permeable cover, and a 78% reduction of DRP in swine manure slurry collected from a shallow under floor pit collection system. A bench-scale up-flow clarifier was designed, constructed, and tested for continuous flow separation of the precipitated struvite in order to provide total phosphorus (TP) removal. The up-flow clarifier was unable to continuously settle struvite particles formed in the bench-scale reactor and provided no significant TP removal through the system. The implication of this work for full-scale systems is discussed.

Heat and Moisture Production of Hy-Line Brown Hens in Aviary Houses in the Midwestern U.S.

Emissions of gaseous compounds and particulate matter are the product of the pollutant concentrations and air exhausted from the fans of mechanically ventilated animal confinements. Direct methods of monitoring exhaust fan operation (mercury tilt, limit/ whisker, and vibration switches) have been reported to have limitations due to mechanical failure and/or the effect of dust, wind, and moisture. The objective of this study was to find a reliable method of monitoring fan operation status. This article describes the development, lab testing, and field use of a fan monitoring system based on an induction-operated current switch (ICS). The ICS is unaffected by the environment and can provide direct measurement of real-time fan operational status by sensing the AC current drawn by the fan motor. A laboratory test of the ICS was performed to simulate a fan off/on duty cycle for a two-year field emissions monitoring study; no ICS failure was recorded. Three studies led by Iowa State University (Southeastern Broiler Gaseous and Particulate Matter Emission, Determining Ammonia and Particulate Matter Emissions from a Midwest Turkey Grow-Out Building, and Feeding DDGS and Other Altered Diets to Egg Laying Hens to Demonstrate Economically Viable Reductions in Ammonia Emissions) used a total of 28, 12, and 50 ICS systems for 24, 16, and 27 months, respectively, without a non-user error related failure. At a unit cost as low as

Performance of a Pilot-Scale Air Sparged Continuous Flow Reactor and Hydrocyclone for Struvite Precipitation and Removal from Liquid Swine Manure

21.45 this method offers a reliable, accurate, and economical way of measuring the real-time operational status of ventilation fans – a critical component of any air emissions monitoring in a mechanically ventilated confinement.

Evaluation of Laboratory Biochemical Methane Potentials as a Predictor of Anaerobic Dairy Manure Digester Biogas and Methane Production

Abstract. In considering hen housing systems, up-to-date heat and moisture production data are essential to producing properly designed and managed ventilation and supplemental heating systems. The aviary system is one housing type under consideration by egg producers. The aviary system has a much lower bird stocking density and thus more freedom of movement for the birds compared to conventional cage housing. This study was conducted to obtain baseline heat and moisture production values for Hy-Line Brown hens in such houses in the Midwestern U.S. House-level thermal environment, gaseous concentrations, and bird production performance of two commercially operated 50,000-hen aviary houses were continually monitored over a 19-month period. The two houses used similar management practices and Hy-Line Brown hens with a 20-week difference in age. Data were collected for a complete flock (17 to 83 weeks, no molt) in each house. Total heat production (THP) of the hens, house-level latent heat production (LHP) or moisture production (MP), house-level sensible heat production (SHP), and respiratory quotient (RQ) were determined from the monitored variables using indirect calorimetry and mass/energy balance, respectively. Variations in THP, LHP/MP, SHP, and RQ within the day were delineated. Results of the study showed mean (±SE) THP, house-level LHP, house-level SHP, and RQ values of 5.94(±0.09) W kg -1 , 1.83(±0.03) W kg -1 , 4.11(±0.08) W kg -1 , and 0.94(±0.01), respectively, for the aviary housing system. The new data will improve the design and operation of building ventilation, supplemental heating, and ultimately production efficiency of aviary housing systems. The THP and RQ data will also be useful to indirect determination of building ventilation rate using the carbon dioxide (CO 2 ) balance method.