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Compared to conventional cage production systems, cage-free (CF) hen housing offers hens more space and opportunities to exercise their natural behaviors (e.g., perching, dust bathing, and foraging). However, CF housing poses a number of inherent environmental challenges, among which are high levels of particulate matter (PM) and ammonia (NH3). Spraying water on CF hen house litter (e.g., 125 mL m-2 per cm of litter depth) has been shown to mitigate generation of PM by 60% to 70% in our previous lab-scale tests. The objectives of this study were to verify the lab-scale findings of PM reduction in a commercial CF hen house in central Iowa and to evaluate the indoor air quality (e.g., PM and NH3 concentrations) and litter moisture content as affected by water spray. The commercial CF house had a nominal capacity of 50,000 laying hens and measured 154 m × 21.3 m × 3.0 m (L × W × H). A water sprinkling system was installed in half of the hen house in the length direction (treatment section), while the other half of the hen house served as the control. For each of the three trials conducted during the winter of 2017-2018, spray dosage (125 mL H2O m-2 per cm of litter depth) was set according to the initial litter depth before spraying. Results show that PM concentration was reduced by 37% to 51% in the treatment section of the CF hen house. The lower reduction efficiency in the field experiment than in the labscale tests was partially attributed to the fact that water spray in the commercial hen house was applied only to the open litter area, and not the litter area under the aviary system, due to limited space. Adjusting the spray dosage according to litter depth is necessary for maintaining an appreciable reduction efficiency. Litter moisture content in the treatment section was 9% to 14% higher than in the control section (15.6% vs. 14% in trial 1, 14.6% vs. 12.2% in trial 2, and 17.7% vs. 14.9% in trial 3), but NH3 concentrations in the treatment and control sections were similar during the field experiment. [ABSTRACT FROM AUTHOR]

A number of chain restaurants, retailers, and grocers in the U.S. have pledged to source only cage-free (CF)eggs in the foreseeable future (e.g., by 2025) due to marketing reasons or concerns over animal welfare. However, CFhousing has some inherent challenges, and a predominant one is poor air quality, i.e., ammonia gas (NH3) and particulatematter (PM), and increased emissions. Spraying a liquid agent such as electrolyzed water (EW) can effectively suppressPM generation of CF henhouse litter. However, liquid spray can enhance NH3 generation because it increases the littermoisture content (LMC). Application of acidic liquid to the litter would help control NH3 while suppressing PM, but concernsarise about the potential corrosive effect of acidic liquid on housing equipment. To overcome this dilemma, this studyevaluated the effect of applying PLT, a commercial poultry litter additive (LA), on NH3 emissions of CF hen litter whilespraying it with neutral EW (NEW) at a rate of 25 mL kg-1 dry litter d-1. The PLT application rates were 0.3, 0.6, and 0.9 kgm-2, denoted as Low-LA, Med-LA, and High-LA, respectively. CF litter was placed inside dynamic emission chambers andautomatically stirred to mimic hen scratching. PLT was topically applied onto the litter on day 1; NEW was sprayed daily for 11 d, followed by a 3 d non-spray period (i.e., 14 d per trial); and each regimen was replicated four times. The ammoniaemission rate (ER) of the control (no LA), Low-LA, Med-LA, and High-LA regimens (mean „bSE) was, respectively, 0.76„b0.05, 0.55 „b0.06, 0.37 „b0.04, and 0.16 „b0.02 g kg-1 dry litter d-1, i.e., 28% to 79% reduction by the treatments. The NH3reduction efficiency was linearly proportional to the PLT application rate, with higher application rate resulting in lowerlitter pH (p < 0.05). At the end of each trial (d14), the Med-LA and High-LA regimens still showed relatively low NH3emissions, suggesting the need for a longer measurement period in future studies. The NEW spray increased LMC by up to60% after 11 once-a-day sprays, which reduced PM2.5, PM10, and TSP levels from 3.83, 6.39, and 7 mg m-3 to 0.07, 0.14,and 0.15 mg m-3, respectively. After a 3 d spray suspension, the PM levels rebounded to 0.72, 1.02, and 1.12 mg m-3 forPM2.5, PM10, and TSP, respectively, due to decreased LMC. Field verification of the mitigation efficacy and an economicassessment of the method are warranted. [ABSTRACT FROM AUTHOR]

Light plays an important role in poultry development, production performance, health, and well-being. Light technology continues to advance, and accordingly new light products are finding applications in poultry operations. However, research concerning responses of young and adult laying hens to light sources is relatively lacking. This study assessed the choice between a Dim-to-Red poultry-specific light-emitting diode (LED) light (PS-LED, correlated color temperature or CCT = 2000K) and a warm-white fluorescent light (FL, CCT = 2700K) by pullets and laying hens (W-36 breed) via preference test. Birds with different prior lighting experiences were evaluated for their light choice, including (1) pullets (14 to 16 weeks of age or WOA) reared under incandescent light (designated as PINC), (2) layers (44 to 50 WOA) under PSLED (LLED) throughout the pullet and laying phases, and (3) layers under FL (LFL) throughout the pullet and laying phases. Each bird category consisted of 12 replicates, three birds per replicate. Each replicate involved a 6-day preference test, during which the birds could move freely between two interconnected compartments that contained PS-LED and FL, respectively. Time spent and feed intake by the birds under each light were measured and then analyzed with generalized linear mixed models. Results showed that regardless of prior lighting experience, birds in all cases showed stronger choice for FL (p = 0.001 to 0.030), as evidenced by higher proportions of time spent under it. Specifically, the proportion of time spent (mean ±SEM) under FL versus PS-LED was 58.0% ±2.9% vs. 42.0% ±2.9% for PINC, 53.7% ±1.6% vs. 46.3% ±1.6% for LLED, and 54.2% ±1.2% vs. 45.8% ±1.2% for LFL. However, the proportions of daily feed intake occurring under FL and PS-LED were comparable in all cases (p = 0.419 to 0.749). The study thus reveals that prior lighting experience of the pullets or layers did not affect their choice of FL versus PS-LED. While the birds exhibited a somewhat stronger choice for FL, this tendency did not translate into differences in the proportion of feed use under each light type. [ABSTRACT FROM AUTHOR]

Laying-hen housing design and management are the most significant factors affecting the generation and release of gaseous ammonia to the atmosphere. Transitioning the hen housing type from traditional high-rise (where manure is stored within the house for about one year) to modern manure-belt style (where manure is removed every 1 to 4 d and placed into long-term storage) has significantly improved in-barn air quality and reduced farm-level ammonia emissions. As a direct result of the advantages, 100% of new construction for U.S. egg production incorporates manure-belt systems that regularly remove manure from the houses. However, manure-belt system designs (e.g., active vs. passive drying of manure on the belt) and management practices (e.g., frequency of manure removal) vary considerably across the industry, leading to large variations in system performance and efficiency. Thus, questions remain about the optimal design and management of manure-belt facilities to achieve the desired reductions in ammonia emissions. As part of the Coalition for a Sustainable Egg Supply (CSES) project, 27 months of continually monitored environmental data (including ammonia and greenhouse gas emissions) were collected from three hen-housing systems: a conventional cage house (CC) with a 200,000-hen capacity, an enriched colony house (EC) with a 50,000-hen capacity, and an aviary house (AV) with a 50,000-hen capacity. All three hen houses were located on the same farm and were populated with Lohmann white hens of the same age. All houses were equipped with manure-drying air ducts above the manure belts using recirculated indoor air (flow rate ranging from 0.46 to 1.49 m³ h-1 hen-1). Manure on the belts was completely removed every 3 to 4 d. Average daily house-level ammonia (NH3) and carbon dioxide (CO2) emissions as affected by manure accumulation time (MAT, from 1 to 4 d) on the manure belts were analyzed. Results indicate that for all three types of houses, NH3 emission rates (g hen-1 d-1) were significantly lower for MAT of 1 and 2 d (mean ±SE of 0.061 ±0.005 and 0.064 ±0.004, respectively) than for MAT of 3 and 4 d (0.085 ±0.005 and 0.115 ±0.007, respectively) (p < 0.001). Emissions of CO2 (g hen-1 d-1) were not significantly affected by MAT, averaging 67.8 ±5.7 for CC, 74.7 ±10.2 for EC, and 75.9 ±10.5 for AV. Estimating annual NH3 emissions from each type of house revealed that shortening the manure removal interval from every 4 d to every 2 d has the potential of reducing NH3 emissions by 27% for the CC and EC houses and by 19% for the AV house. However, verification of the potential reductions is needed. [ABSTRACT FROM AUTHOR]

Ground transport of pigs at early ages may result in profit-stripping incidences of mortality and compromised animal welfare due to stress stemming from unfavorable transport conditions. The objective of this study was to examine possible causative relationships of mortality rate of weaned and feeder pigs to ground transport conditions. A total of 7056 transportation records of weaned pigs (3174 records) and feeder pigs (3882 records) for the period from April 2012 to January 2014 were provided by a U.S. swine company. Effects of pig type (weaned vs. feeder pigs), ambient temperature (<15°C or cool/cold, 15°C to 25°C or mild, and >25°C or warm/hot), travel distance (<600 km, 600 to 900 km, 900 to 1200 km, 1200 to 1500 km, and >1500 km), and the interactive effects on dead-on-arrival (DOA) rate (DOA per head loaded, %) were evaluated. The effects of the same variables on post-transport mortality of weaned pigs were also evaluated. Results show that DOA rate was affected by pig type, ambient temperature, and travel distance interactively. Weaned pig DOA rates (mean ±SE of 0.0333% ±0.0150%) tended to be higher than feeder pig DOA rates (0.0243% ±0.0110%) (p = 0.0004), and weaned pigs were more vulnerable to transport stress in warm/hot conditions. For weaned pigs, DOA rates were higher with >900 km travel distance (0.0543% ±0.0389%) than with <900 km travel distance (0.0118% ±0.0078%) in cool/cold conditions, and DOA rates significantly increased as travel distance increased in warm/hot conditions. For feeder pigs, DOA rates were not affected by travel distance in cool/cold or mild conditions; however, higher mortality rates were found with >1200 km travel distance (0.2717% ±0.1326%) than with <1200 km travel distance (0.0315% ±0.0151%) in warm/hot conditions. Statistical analysis showed that post-transport mortality rate of weaned pigs was affected by ambient temperature during transport and travel distance interactively for the first one or two weeks after transport. However, it should be noted that the relationship between post-transport mortality and transport conditions could have been confounded by other factors, such as management at the finishing farm. Outcomes of this study are expected to offer insight into improving the ground transport of pigs. [ABSTRACT FROM AUTHOR]

Anaerobic digestion is one of the most popular methods for swine manure treatment in China, and the resultant digestates are mainly used as fertilizer on arable land. Residues from anaerobic fermentation may be used to mitigate the use of chemical fungicides, but relevant information is lacking. In this lab-scale study, original digestate (OD) from a swine manure-fed digester and centrifuged supernatant liquid (SL) with different storage times (0, 7, 14, or 28 d) were added to potato dextrose agar (PDA) media at a rate of 5% to investigate the effects on in vitro mycelial growth of seven phytopathogenic fungi: Fusarium oxysporum, Sclerotinia sclerotiorum, Rhizotonia cerealis, Bipolaris sorokinianum, Rhizoctonia solani, Exserohilum turcicum, and Bipolaris maydis. Diameters of the fungal colonies were measured at 1 d intervals for 7 consecutive days, and the absolute growth rate (AGR) and growth coefficient (k) were calculated. Results showed that the colony sizes of Fusarium oxysporum, Sclerotinia sclerotiorum, Rhizotonia cerealis, Bipolaris sorokinianum, and Rhizoctonia solani on the OD-treated media were significantly smaller (p < 0.01) than the corresponding controls regardless of the storage time. Similarly, independent of storage time, SL-treated media were shown to significantly (p < 0.01) suppress AGR compared to the controls for all seven fungi except for Exserohilum turcicum, where no significant difference was observed between the 14-day-old SL treatment and control. The average k values of the fungi on the OD-treated media ranged from 29% to 143% of the values on the SL-treated media. The results of this study suggest potential use of digestate for plant disease control, which would reduce the use of chemical fungicides. Further studies are needed to investigate the fungicidal mechanism and fungicidal efficacy of OD and SL under field conditions. [ABSTRACT FROM AUTHOR]

Current recommendations for swine building ventilation system design to maintain an environment conducive to animal productivity and well-being are based on heat and moisture production rates measured in the 1950s and 1970s. Advancements in animal genetics, nutrition, and management practices to increase productivity and pork quality since then have led to considerable changes in heat and moisture production rates of modern swine and their housing systems. This study quantifies the total heat production rate (THP) of the animals, which is partitioned into house-level latent heat or moisture production rate (LHP, MP) and house-level sensible heat production rate (SHP), of a 4300-sow breeding, gestation, and farrowing facility in Iowa for 16 consecutive months. The THP was determined using indirect animal calorimetry, LHP or MP was determined from mass balance, and SHP was calculated as the difference between THP and LHP. A mobile air emission monitoring unit equipped with state-of-the-art gas analyzers and a data acquisition system was used to monitor the deep-pit breeding and early gestation barn [1800 head, 204 ±3.2 kg head-1 (mean ±SE)], the deep-pit late gestation barn (1800 head, 219 ±3.0 kg head-1), and two shallow-pit (pull-plug) farrowing rooms (40 sows with litters per room, 223 ±0.4 kg head-1). Results from the study show that THP at 20°C averages 1.89 W kg-1 for sows in the breeding and early gestation stage, 1.57 W kg-1 for sows in the late gestation stage, and 3.35 W kg-1 for sows and litters in week 0 of the lactation stage. The corresponding house-level LHP for the three stages averages 0.74 W kg-1 (early gestation), 0.57 W kg-1 (late gestation), and 1.98 W kg-1 (lactation, week 0). Finally, the corresponding house-level SHP for the three stages averages 1.15 W kg-1 (early gestation), 1.00 W kg-1 (late gestation), and 1.37 W kg-1 (lactation, week 0). Compared with the ASABE Standards, the values from the current study for gestation sows in their early and late pregnancy stages showed increases of 35% and 12% in THP, 72% and 34% in LHP, and 19% and 3% in SHP, respectively. Values for lactating sows and litters during the first week after parturition showed changes of 29% in THP, 52% in LHP, and 6% in SHP relative to the ASABE Standards. The reductions of THP from day to night for the three stages were 30% (early gestation), 27% (late gestation), and 6% (lactation). These data will help with updating the standards for ventilation design and operation of modern swine housing. [ABSTRACT FROM AUTHOR]

Housing design and management schemes (e.g., bird stocking density) in egg production can impact hens' ability to perform natural behaviors and production economic efficiency. It is therefore of socio-economic importance to quantify the effects of such schemes on laying-hen behaviors, which may in turn have implications on the animals' wellbeing. Video recording and manual video analysis is the most common approach used to track and register laying-hen behaviors. However, such manual video analyses are labor intensive and are prone to human error, and the number of target objects that can be tracked simultaneously is small. In this study, we developed a novel method for automated quantification of certain behaviors of individual laying hens in a group-housed setting (1.2 m x 1.2 m pen), such as locomotion, perching, feeding, drinking, and nesting. Image processing techniques were employed on top-view images captured with a state-of-the-art time-of-flight (ToF) of light based 3D vision camera for identification as well as tracking of individual birds in the group with support from a passive radio-frequency identification (RFID) system. Each hen was tagged with a unique RFID transponder attached to the lower part of her leg. An RFID sensor grid consisting of 20 antennas installed underneath the pen floor was used as a recovery system in situations where the imaging system failed to maintain identities of the birds. Spatial as well as temporal data were used to extract the aforementioned behaviors of each bird. To test the performance of the tracking system, we examined the effects of two stocking densities (2880 vs. 1440 cm2 hen-1) and two perching spaces (24.4 vs. 12.2 cm of perch per hen) on bird behaviors, corresponding to five hens vs. ten hens, respectively, in the 1.2 m x 1.2 m pen. The system was able to discern the impact of the physical environment (space allocation) on behaviors of the birds, with a 95% agreement in tracking the movement trajectories of the hens between the automated measurement and human labeling. This system enables researchers to more effectively assess the impact of housing and/or management factors or health status on bird behaviors. [ABSTRACT FROM AUTHOR]

Carbonaceous and nitrogenous gases are produced during storage of livestock manure, with the magnitude of production being affected by the chemical properties of the manure and the physical conditions of storage. This lab-scale study quantifies the emission rates of ammonia (NH3), nitric oxide (NO), and greenhouse gases (GHG), i.e., methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), from biogas digester effluent (BDE) stored at different depths of 1.0, 1.5, and 2.0 m in dynamic emission vessels (DEVs). The selected storage depths were reflective of the typical depth range of on-farm BDE storage in China. The static storage was held at a relatively constant media temperature of 15°C and an air exchange rate of 11.5 air changes per hour (ACH) for 78 days. Each depth regimen was replicated four times using four DEVs (12 DEVs total). The results showed that the mean (±SE) daily gaseous emission rates per volume of BDE stored at 1.0, 1.5, and 2.0 m depths, in g gas m-3 d-1, were, respectively, 9.1 (±0.7), 10.1 (±0.6), and 10.1 (±0.4) for CH4 (p = 0.39); 38.0 (±2.2), 34.5 (±1.3), and 30.7 (±0.6) for CO2 (p < 0.05); 1.9 (±0.11), 1.3 (±0.08), and 0.9 (±0.03) for NH3 (p < 0.05); and 6.7 (±0.5) x 10-3, 5.0 (±0.8) x 10-3, and 3.4 (±0.2) x 10-3 for N2O (p < 0.05). Nitric oxide (NO) emissions were negligible. The overall GHG (CH4 + N2O + CO2) emissions were dominated by CH4, which accounted for more than 85% of the CO2-equivalent emissions for all three storage depths. The CH4 emissions peaked during the early storage period, with the first 20-day cumulative emissions accounting for 56% to 58% of the total 78-day storage emissions. The results reveal that storage of BDE at 2.0 m depth yielded lower CO2, NH3, and N2O emission rates but similar CH4 emission rates compared to the 1.0 and 1.5 m depths. [ABSTRACT FROM AUTHOR]

Biogas digesters are commonly used in livestock farming in China. The digestion process converts large amounts of raw liquid manure (RLM) to biogas digester effluent (BDE). The BDE is then stored on the farm for some time before land application as crop or orchard nutrients. Storage of RLM or BDE is associated with gas emissions, although little information is available concerning comparison of air emissions between the two handling practices. This study was conducted to compare methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), and ammonia (NH3) emissions from RLM and BDE storages using dynamic emission vessels (DEVs). Both media were stored in closed vessels (50 L) at a 40 cm storage depth, a constant storage temperature of 30°C, and a headspace air exchange rate of 15 to 17 air changes per hour (ACH) for 22 days. The results showed that the average daily gas emission rates for RLM and BDE, in mg L-1 d-1, were, respectively, 102.9 and 125.3 CO2 (p < 0.05), 0.72 and 3.33 N2O (p < 0.05), 29.2 and 0.32 CH4 (p < 0.05), and 1.21 and 0.66 NH3 (p = 0.08). The total greenhouse gas (GHG = CH4 + CO2 + N2O) emissions were similar for RLM and BDE, 1.05 and 1.12 g CO2-eq L-1 d-1, respectively (p = 0.26). Nitrous oxide (N2O) emissions accounted for 88.2% of the CO2-eq GHG emissions for BDE, whereas CH4 emissions accounted for 69.7% of the CO2-eq GHG emissions for RLM. The high N2O emissions from BDE likely resulted from the lower COD/N ratio in BDE than RLM under the storage conditions. Differences in gaseous emission characteristics between RLM and BDE were attributed to the differences in methanogen species and the population of ammonia-oxidizing bacteria (AOB). [ABSTRACT FROM AUTHOR]

Compared to conventional cage laying-hen houses, aviary hen houses generally have much higher concentrations of airborne dust and bacteria due to generation of bioaerosols by the hens' access to and activities on the litter floor. Hence, reducing these airborne agents is important to safeguard the health of the animals and workers in such housing systems. Spraying slightly acidic electrolyzed water (SAEW) is a novel approach to reducing airborne culturable bacteria (CB) and particulate matter (PM) levels in hen houses. The objective of this study was to evaluate the efficacy of reducing airborne CB and PM in an experimental aviary chamber by periodic spraying of SAEW (Trt), as compared to no spraying (Ctrlns) or spraying of tap water (Ctrlw). The hens were provided 16 h light and 8 h dark (lights on at 6:00 h and off at 22:00 h) and were given access to the litter floor from 12:00 h to 22:00 h. The Trt regimen sprayed SAEW at 14:00 h for 15 min at a dosage of 80 mL m-2; the Ctrlns regimen had no spraying; and the Ctrlw regimen sprayed tap water following the same procedure as with Trt. Concentrations of airborne CB and PM in six aerodynamic size ranges (0.65-1.1, 1.1-2.1, 2.1-3.3, 3.3-4.7, 4.7-7.1, and >7.1 µm) were measured at 1.5 m above the floor in the center of the room during the periods of 13:45-14:00 h and 14:45-15:00 h. Compared to Ctrlns, spraying SAEW significantly reduced airborne CB (>2.1 µm) by up to 49% ±10% (p < 0.05), while Ctrlw did not show a reduction effect. No significant difference was found between Trt and Ctrlw in reducing airborne PM, although both reduced or tended to suppress PM >7.1 µm in size. The results show that spraying SAEW can inactivate airborne CB attached to PM. Thus, this is a promising technique for alleviating the adverse health impacts of bioaerosols in aviary laying-hen housing systems. [ABSTRACT FROM AUTHOR]

The effect of ventilation rate (VR) on ammonia and greenhouse gas emissions from co-composting dead hens mixed with hen manure was quantified. Three VR levels of 0.9, 0.7, and 0.5 m³ h-1 were evaluated. Gaseous concentrations were measured using a multi-gas infrared photoacoustic analyzer, VR was measured with flowmeters, and the gas emission rate was computed from the VR and gas concentration. Decomposition of the carcasses over the 11-week composting period was greater than 88%. VR was found to significantly affect NH3, CO2, and CH4 emissions (p < 0.05). Specifically, cumulative emissions per kg of initial matter for VR of 0.9, 0.7, and 0.5 m³ h-1 were, respectively, 2.4, 2.0, and 1.2 g NH3; 78, 66, and 42 g CO2; 120, 90, and 52 mg CH4; and 6.4, 6.1, and 5.1 mg N2O. Hence, the study results suggest that the ventilation rate can be adjusted to reduce NH3 and GHG emissions from animal mortality compositing. [ABSTRACT FROM AUTHOR]

Maintaining comfortable thermal environments and good indoor air quality is essential to ensuring optimal production performance, welfare, and health of animals. Alternative laying-hen housing systems are being adopted by some egg producers in the U.S. However, information on indoor thermal and aerial environments of such alternative housing systems is meager. This article reports a one-year monitoring of thermal conditions (air temperature and relative humidity or RH) and ammonia (NH3) concentrations and emissions of four aviary laying-hen houses (same dimensions, manure belt plus litter floor systems, 50,000-hen capacity each) at a commercial farm in the Midwest U.S. Carbon dioxide (CO2) concentrations at the air inlet and near the exhaust.fans were measured and used, along with literature values of the metabolic rates of the hens, to estimate building ventilation rate (VR). The results show that indoor temperature, RH, CO2 concentration, NH3 concentration, and VR of the four houses (mean ± standard deviation) were 23.4°C ±0.3°C, 64% ±3%, 1520 ±87 ppm, 5.2 ±0.4 ppm, and 4.5 ±0.6 m³ h-1 hen-1 respectively. The highest daily mean NH3 concentration was 13 ppm (and 20 ppm within the day) in winter. The NH3 emission rate was 0.14 ŷ0.01 g d-1 hen-1 These values of NH3 concentrations and emissions were lower than those reported for European aviary houses. The NH3 emissions of the monitored aviary houses in this" study are comparable to those of U.S. manure-belt cage houses, but are much lower than those of U.S. high-rise cage houses. The magnitude of NH3 emissions observed in this study was consistent with that of similar aviary houses with brown hens in another extended field measurement in the same region. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of dietary forage type and concentrate-to-forage ratio (CTFR) on CH4 emissions from dairy cows in China using the SF6 tracer method Rumen fluid concentrations of NH4-N and VFA, rumen fluid pH, and daily milk yield were measured as well The dietary regimens included: corn stalks (dry corn stalks after corn harvest) as the forage source at CTFR of 40:60 (ration A), corn silage as the forage source at CTFR of 40:60 (ration B), and corn silage as the forage source at CTFR of 60:40 (ration C). Twelve dairy cows (body weight = 525 ±12 kg, mean ± SE) were divided into three groups of four animals each, balanced in age and body weight, and randomly allocated to the dietary treatments. The study was run for 25 days, with the first 15 days used for adjustment and the subsequent 10 days used for response measurement. The dietary treatments ranked ration A > ration B > ration C for CH4 emissions quantity (L d-1 head-1 ), rumen fluid pH, acetic acid concentration, and ratio of acetic acid and propionic acid concentration. For example, CH4 emissions (mean ±SE) for rations A, B, and C were 353±13.4, 283±7.48, and 263 ±9.04 L d-1 head -1, respectively, or 335 ±12.75, 270 ± 7.12, and 250 ± 8.6 L d-1 AU-1 (AU = 500 kg live weight). On the other hand, the treatments ranked ration A < ration B < ration C for concentrations of NH3-N, propionic acid, and butyric acid in the tureen fluid This study indicates that CH4 emissions intensity from dairy cows (g kg-1 milk output) can be significantly reduced by using corn silage as a forage source and by increasing the content of concentrates in the ration. Compared with rations B and C, ration A increased CH4 emissions by 25% and 34% (p < 0.01), respectively. A full assessment of the effectiveness of such an improved feeding management, through life cycle analysis, in reducing carbon footprint would be warranted in future studies. [ABSTRACT FROM AUTHOR]

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 (CO2) balance method. [ABSTRACT FROM AUTHOR]

Data on ammonia (NH3) emissions from pullets (hens <18 weeks of age) are non-existent despite the large differences in nutritional and environmental conditions between raising pullets and laying hens. Different stocking densities (SDs) in housing the birds may be used according to certain industry guidelines on production; however, information concerning the impact of SD on properties of accumulated manure and thus NH3 emissions is limited in the literature. It was hypothesized that bird SD affects the amount of manure per unit of storage or surface area as manure accumulates, and the exposed manure surface area may in turn affect NH3 emission from the accumulated manure. A lab-scale study was conducted that resembled the conditions of manure-belt laying-hen houses with the objectives of (1) determining the magnitude ofNH3 emission rate (ER) of pullets (W-36 breed) as a function of age, and (2) assessing the effect of SD on NH3 ER of pullets and laying hens during a 6-day manure accumulation time (MAT). Two SDs at a given bird age (4 to 37 weeks) were evaluated, ranging from 155 and 206 cm² to 413 and 620 cm² (24 and 32 in.²2 to 64 and 90 in.²) per bird, designated as high density (HD) and low density (LD), respectively. Ammonia ER was expressed on the basis of per bird, per animal unit (AU, 500 kg live body weight), per kg of feed nitrogen (N) use, and per kg of as-is or dry manure. Results showed that daily NH3 ER for pullets and laying hens increased exponentially with bird age and MAT (p < 0.0001). Compared to the HD regimen, the LD regimen had 51% lower NH3 ER (in mg bird-1 d-1) for 4- to 5-week-oldpullets and averaged 22% lower for laying hens. Results of this study provide a scientific basis concerning the impact of certain management practices on NH3 emissions and offer insight into reducing NH3 emissions from egg production operations. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) emissions from laying hens are affected by nutrient content of the diet, manure quantity, and manure properties such as moisture content, nitrogen content, and pH. These production traits may vary with strain of the hen. However, limited information is available concerning the effects of laying-hen genetics on manure properties and NH3 emission. This study was conducted to comparatively quantify production performance, manure properties, and NH3 emissions (through N mass balance) of four white-egg-laying strains (Hy-Line W-36, Hy-Line W-98, Lohmann LSL Lite, and Bovans White) and four brown-egg-laying strains (Hy-Line Brown, Lohmann Brown, ISA Brown, and Bovans Brown) during two production periods of 27-28 weeks (PI) and 35-36 weeks (P2) of age. The diets were formulated to meet the nutritional needs of the brown and white hens. As a result, crude protein contents during PI and P2 were, respectively, 13.2% and 15.2% for the brown hens but 14.5% and 17.4% for the white hens. The results showed that the brown and white hens had similar hen-day egg production (97.5% to 89.2% for brown hens and 96.0% to 88.2% for white hens) and egg mass output (57.1 to 52.6 g d-1 hen-1 for brown hens and 55.6 to 51.2 g d-1 hen-1 for white hens) but different feed consumption (112 to 98 g d-1 hen-1 for brown hens and 101 to 93 g d-1 hen-1 for white hens, p < 0.01) and feed efficiency (1.97 to 1.87 g feed g-1 egg for brown hens and 1.82 g feed g-1 egg for white hens, p < 0.0001 and p = 0.11). The higher feed consumption for the brown hens stemmed from their heavier body mass (1.81 to 1.78 kg vs. 1.56 to 1.53 kg for white hens). Manure moisture content was higher for the brown hens than for the white hens, although the dry-matter manure production was not significantly different. The results further revealed that under the experimental conditions (i.e., higher CP contents of the diet for the white hens than for the brown hens) the white hens had higher NH3 emissions than the brown hens as expressed per hen (37% to 19% higher, p = <0.001 to 0.016), per animal unit (AU, 500 kg live body mass; 59% to 39% higher, p = 0.0007 to 0.007), per unit of egg mass output (41% to 24% higher, p = 0.01 to 0.09), per unit of feed N consumed (39% to 27% higher, p = 0.01 to <0.0001), and per unit of dry manure (56% to 39% higher, p = 0.001 to 0.007). Certain differences existed in production performance among strains within the brown or white hens, but no differences in NH3 emissions were detected. Because of the relatively small sample size (number of hens involved) and the relatively short monitoring period, the results should be referenced with these limitations in mind. Further larger-scale studies with longer monitoring periods to verify these findings are warranted. [ABSTRACT FROM AUTHOR]

This study quantifies concentrations and emission rates (ER) of ammonia (NH3) and greenhouse gases (GHG) including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from a naturally ventilated cage layer (Hy-Line brown strain) house with daily manure removal, located in northeast China during four seasons of one year, with each monitoring episode lasting five consecutive days. Gaseous concentrations of background and exhaust air were measured using an infrared photoacoustic multi-gas monitor with a multi-channel sampler. Building ventilation rate (VR) was determined by CO2 mass balance using literature metabolic rate data for modern laying hens. Both gas concentrations and ER showed considerable diurnal and seasonal variations. Annual mean (±SD) ER of NH3, CO2, CH4, and N2O for the monitored layer house were, in mg d-1 bird-1, 129 ±40.3, 78,250 ±15,384, 112 ±56.5, and 9.4 ±2.5, respectively, or in g d-1 AU-1 (AU = 500 kg live body weight), 33.4 ±11.4, 19,975 ±3,071, 29.2 ±15.2, and 2.5 ±0.7, respectively. Ammonia ER from the current study was within the ranges of values reported for high-rise houses with annual manure removal and manure-belt houses with daily manure removal. Results of the study contribute to improving ammonia and GHG emissions inventory for animal feeding operations in China and worldwide. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) associated with animal feeding operations is a concern for the occupants and the surrounding community. Baseline measurements of PM concentration and emission rate are the first step toward assessing the magnitude of concentrations and emissions and evaluating effectiveness of dust control strategies. This study presents the results of PM measurements at a high-rise layer house (approx. 250,000 hens) in central Iowa using tapered element oscillating microbalance (TEOM) equipment. Daily average concentrations of PM10 and PM2.5 over a 17-month measurement period were 393 (±257 SD) and 44 (±36 SD) µg m-3, respectively. Daily average PM10 and PM2.5 emission rates during the same monitoring period were, respectively, 26.1 (±15.8 SD) and 3.6 (±3.7 SD) mg bird-1 d-1, or 8.16 (±4.94) and 1.13 (±1.16) g AU-1 d-1 (AU = animal unit = 500 kg body weight). PM emission rate was positively related to ventilation rate but was negatively related to relative humidity. [ABSTRACT FROM AUTHOR]

Limited data exist in the literature regarding air emissions front U.S. turkey feeding operations. The project described in this article continuously monitored ammonia (NH3) and particulate matter (PM) emissions front turkey production houses in Iowa (IA) and Minnesota (MN) for 10 to 16 months, with IA monitoring Hybrid tom turkeys (35 to 143 d of age, average market body weight of 17.9 kg) for 16 months and MN monitoring Hybrid hens (35 to 84 d of age, average market body weight of 6. 7 kg) for 10 months. Mobile air emission monitoring units (MAEMUs) were used in the continuous monitoring. Based on the approximately one-year measurement, each involving three flocks of birds, daily NH3, PM10, and PM2.5 concentrations (mean ±SD) in the tom turkey barn were 8.6 + 10.0 ppm, 1104 ± 719 µg m-3, and 143 (±124)µg m-3, respectively. Daily NH3 and PM10 concentrations (mean ±SD) in the hen turkey barn were 7.3 ± 7.9 ppm and 301 ± 160 µg m-3, respectively. Daily NH3 concentrations during downtime (mean ±SD) were 38.4 ± 20.5 and 20.0 ± 16.3 ppm in the tom and hen barns, respectively. The cumulative NH3 emissions (mean ±SE) were 141 ± 13.1 and 1.8 ± 0.9 g bird-1 for the tom turkeys during 108 d growout and 13 d downtime, respectively, and 52 ± 2.1 and 28.2 ± 2.5 g bird-1 for the hen turkeys during 49 d growout and 32 d downtime, respectively (the extended downtime for the hen house was to ensure monitoring of one flock per season). The cumulative PM10 emission (mean ±SE) was 28.2 ± 3.3 g bird-1 for the tom turkeys during 108 d growout and 4.6 ± 2.2 and 0.3 ± 0.06 g bird-1 for the hen turkeys during 49 d growout and 32 d downtime, respectively. Downtime in the hen house was of greater duration than would be typically observed (32 d vs. 7 d to 14 d typical). The cumulative PM2.5 emission (mean ± SE) was 3.6 ± 0.7 g bird-1 for the tom turkeys during 108 d growout (not monitored for the hen turkeys). Because farm operations will vary in flock number, growout days, and downtime; annual emissions can be calculated front the cumulative emissions and downtime emissions per bird from the data provided. Air emissions data from this study, presented in both daily emission and cumulative per-bird-marketed emission, contribute to the improved U.S. national air emissions inventory for animal feeding operations. [ABSTRACT FROM AUTHOR]

Manure-belt (MB) and high-rise (HR) laying-hen houses are the two predominant housing types in the U.S. Compared with HR houses, MB houses have better indoor air quality and lower aerial emissions as a result of frequent (every 1 to 4 d) manure removal from the hen houses into separate manure storage. However, emissions from on-farm manure storage are integral parts of the whole-farm emissions and need to be quantified. This series of lab-scale studies assesses emission rates (ER) of ammonia (NH3) and greenhouse gases (CH4, CO2, and N2O) from stored laying-hen manure as affected by the following physical and environmental factors: air exchange rate (10 or 20 air changes per hour, or ACH), manure stacking configuration expressed as surface area to stack volume ratio (SVR at 2.5, 5, 10, or 20 m-1), air temperature (constant at 25°C or diurnal cyclic from 21°C to 32°C), manure moisture content (MC, 50% or 77%), and periodic addition of new manure to the existing stack. Results of the studies showed the following: (1) air exchange rate of 10 or 20 ACH had no apparent effects on the gaseous emissions; (2) SVR significantly affected emissions, with larger SVR leading to higher NH3 and CO2 ERs but lower CH4 ER on per kg manure basis; (3) emissions were positively related to air temperature; and (4) laying-hen manure with 77% MC had higher emissions than that with 50% MC. At the storage condition of 25°C air temperature, 20 ACH, every 2 d addition of 120 kg (5 cm thick layer) manure at 75% MC (equivalent to 2 d manure production of 682 laying hens) to the flat base area of 2.8 m², the daily gaseous ERs per hen were 0.06 to 0.22 g NH3, 1.6 to 4.8 g CO2, and 7.4 to 32 mg CH4 (0.18 to 0.8 g CO2e). N2O concentrations from the stored manure were below the detection limit (0.03 ppm) of the measurement instrument; hence, N2O emission was omitted from the presentation. [ABSTRACT FROM AUTHOR]

Accurate ventilation rate (VR) data are essential to maximizing the quality of aerial emission measurements. The Fan Assessment Numeration System (FANS) has been widely used by U.S. researchers in measuring aerial emissions from mechanically ventilated livestock and poultry facilities. The FANS device is used to measure airflow rates of ventilation fans in situ, thereby developing fan performance curves under field conditions. The FANS device was originally intended to be placed upstream of the fan to be calibrated. However, certain field situations make it impractical to apply the FANS device as such. This study was conducted to assess use of the FANS device downstream of a ventilation fan, with the gaps between the FANS device and the discharge cone of the exhaust fan sealed using a non-permeable fabric. Nine exhaust fans (1.22 or 1.32 m diameter) in laying hen and turkey houses were tested with the FANS device placed upstream and downstream for a building static pressure range of 10 to 40 Pa. The results revealed that downstream placement of the FANS device yielded 0.6% ± 0.4% to 4.0% ± 0.9 % (mean ± SE) higher but not significantly different (P > 0.28) VR values as compared to upstream placement for the exhaust fans tested. This magnitude of discrepancy is considered acceptable for in situ measurement of fan performance. [ABSTRACT FROM AUTHOR]

Current and relevant heat and moisture production data for laying hens are necessary for sizing and operating ventilation systems for commercial layer housing. Different stocking densities are being adopted in cage layer facilities, but there is a lack of information concerning the potential impacts of these changes on environmental control. A study was conducted with 24 groups of 48 hens (39 to 46 weeks old) to compare heat and moisture production, via indirect calorimetry, for four different stocking densities (348, 387, 465, or 581 cm² hen-1; 54, 60, 72, or 90 in.² hen-1) and two group sizes (8 or 16 hens per cage). Data were collected under thermoneutral (24 ° C or 76 °F) and heat-challenging conditions (32 °C or 90 °F and 35 °C or 95 °F). No notable differences in heat and moisture production were observed among the treatments under the experimental conditions. Room-level 24 h time-weighted mean sensible heat production, latent heat production or moisture production, and total heat production, respectively, were found to be 2.8 to 3.1 W kg-1, 3.5 to 3.7 W kg-1, and 6.4 to 6.6 W kg-1 at 24 °C; O. 7 to 1.0 W kg-1, 4.9 to 5.2 W kg-1, and 5.6 to 6.1 W kg-1 at 32 °C; and -1.0 to -0.4 W kg-1, 5.9 to 6.5 W kg-1, and 5.4 to 5.7 W kg-1 at 35 °C. These results imply that for existing laying hen houses, reducing stocking density, and thus flock size, will reduce the heat and moisture generated within the houses. This may lead to difficulties in maintaining desired temperatures without compromising air quality during cold weather, but reducing stocking density may offer benefits for heat stress prevention and relief during hot weather. [ABSTRACT FROM AUTHOR]

Sectors of the U.S. cage layer industry have begun adopting practices of reduced stocking density (i.e., increased cage floor space per hen) and varying group sizes. This study was conducted with 24 groups of 48 W-36 laying hens (39 to 46 weeks old) to assess the effects of cage floor space or stocking density (SD) (348, 387, 465, or 581 cm² hen-1; 54, 60, 72, or 90 in.² hen-1) and group size (GS) (8 or 16 hens per cage) on the ability of the hens to cope with heat challenge. Data were collected at thermoneutral (24 °C or 76 °F) and warm conditions (32 °C or 90 °F, followed by 35 °C or 95 °F). No differences in core body temperature (CBT) of the hens were observed among the treatment regimens at 24°C. In general, mean CBT increased with heat exposure duration (P < 0.0001) but leveled off after the 32 °C phase. At 32 °C, CBT was higher for GS of 16 vs. 8 (42.3 °C vs. 42.1 °C, P = 0.05) and higher for SD of 348 and 387 cm² hen-1 than for 465 or 581 cm² hen-1 (42.4 °C and 42.2 °C vs. 41.9 °C and 42.1 °C, respectively, P = 0.009). Bird body mass decreased as heat exposure duration increased (P < 0.0001), but no differences were observed among the treatments. No mortalities were observed during the thermoneutrality period, and the mortality rate increased with heat exposure duration. The results indicate that, while CBT was lower for lower SD, the increased space was not sufficient to offer a clear benefit for coping with heat challenge of 32 °C followed by 35 °C. [ABSTRACT FROM AUTHOR]

Ventilation rate (VR) is one of the two key elements for quantifying aerial emissions from animal production facilities. Direct, continuous measurement of building VR can be challenging and impractical under certain circumstances, e.g., naturally ventilated animal housing or a large number of ventilation fans in the building. This study examined the suitability of estimating VR of broiler houses with built-up litter (mixture of manure and bedding), when supplemental heating was not in use, through either carbon dioxide (CO2) balance or the relationship of VR to CO2 concentration difference between exhaust and inlet air. The reference VR was based on direct measurement by continuously monitoring operation of the in-situ calibrated exhaust fans. The comparative analysis of the direct method vs. each indirect method was conducted for a measurement integration time (MIT) of 10, 30, 60, or 120 min. The analyses revealed that MIT of 30 min or greater resulted in non-significant differences in VR between the indirect and direct methods. The broiler building VR (m3 s-1) may be related to the exhaust-inlet CO2 concentration difference (ΔCO2, ppm) as VR (±3.0) = 4456 (±41) ΔCO2-0.786(±0.019) at 30 min MIT. The VR may also be determined by the CO2 balance method (including litter CO2 generation) with a correction factor of 0.97 at MIT of 30 to 120 min. If litter CO2 generation is omitted from the total building CO2 production, the actual VR may be estimated by applying a correction factor of 1.077 to the bird respiration CO2 balance VR. Hence, the CO2 balance or concentration difference method offers a viable alternative or supplemental check for quantifying building VR under certain conditions where direct, continuous VR measurement is not feasible. [ABSTRACT FROM AUTHOR]

Gas analyzers are commonly protected from impurities in air sampling via use of in-line dust filters to ensure operational performance and longevity of the instruments. This is especially true with extended periods of air quality monitoring in dusty environments. Prices for commercially available filters and monitoring needs vary considerably. A question that has often come up but has not received much investigation is how the filter media types (e.g., paper vs. Teflon) and operational conditions (clean vs. dirty) impact the integrity of gaseous concentration measurement. The study reported here was conducted toward addressing this issue. Specifically, the study assessed the magnitude of ammonia (NH3) adsorption for several types of in-line filters and conditions often used or encountered in animal feeding operation air emission studies, namely, Teflon (most expensive), paper (least expensive), and stand-alone automobile fuel filters, being either clean (new) or dust-laden. Three nominal NH3 levels (20, 45, or 90 ppm, generated with poultry manure) coupled with two nominal airflow rates (4 vs. 8 L/min or 8 vs. 16 L/min) through the filters were used in the evaluation. The types of dust used in the study included corn starch and broiler-house dust. Simultaneous measurements of NH3 concentrations before and after the tested filter were made with two photoacoustic gas spectrometers. The results revealed that NH3 adsorption was highest for the fuel filter initially but negligible for the Teflon filters. However, after 30 min exposure, relative NH3 adsorption by the filters mostly fell below 1%. The higher flow rate led to significantly lower relative NH3 adsorption for both the fuel and paper filters (P < 0.001) but made no difference for the Teflon filters (P = 0.31 to 0.49). During fresh-air purging of the fuel filters laden with broiler-house dust, NH3 was initially released but diminished after 15 min. The results suggest that when used properly (e.g., proper flow rate), the in-line dust filters tested in this study (fuel, paper, and Teflon) offer viable, performance-based options for air emissions (especially NH3) measurement applications. [ABSTRACT FROM AUTHOR]

This study was conducted to quantify heat and moisture production (HMP) of W-36 laying hens in their prime laying phase (27 to 33 weeks of age) using four large-scale indirect animal calorimeters. Two experiments were conducted involving two groups of hens. The hens were exposed to conditions of 24°C to 27°C and concomitant relative humidity (RH) of 45% to 65% for six weeks. In each experiment, a total of 216 laying hens were used, with 54 hens housed in each of the four calorimeters at the cage stocking density of 435 cm² hew-1 (67 in.² hen that was typical of industry practice. Total heat production (THP), room-level latent heat production (LHP), and room-level sensible heat production (SHP) were expressed as daily time-weighted average (TWA), with an average of 16 h light and 8 h dark. The results showed that HMP was similar for the 24°C to 27°C temperature range. THP, LHP, and SHP, in W kg-1 (mean ±SE) were, respectively, 6.1 ±0.3, 2.3 ±0.2, and 3.8 ±0.1 for the daily TWA; 6.5 ±0.3, 2.4 ±0.2, and 4.1 ±0.1 for the light period; and 5.4 ±0.3, 2.2 ±0.2, and 3.2 ±0.1 for the dark period. The HMP data contribute to the design and operation of ventilation systems in modern laying hen housing. [ABSTRACT FROM AUTHOR]

Analysis of the propagation of measurement error into a computed quantity such as building aerial emissions provides insight into which measurements are most critical and which would have the most impact on the computed quantity if improved. An analysis of different instrument measurements, sampling periods, and sites together comprise an objective means of determining optimal sampling strategies for measurements used to compute aerial emissions from livestock facilities. This article describes the uncertainty analysis for a measurement system used in emissions research, and how it can lead to improvements in measurement system design and implementation to obtain estimates of uncertainty in emissions. The system analyzed was used in a broiler house emission monitoring project that was part of the U.S. EPA Air Consent Agreement. The project required U.S. EPA category I Quality Assurance Project Plan (QAPP) Data Quality Objectives (DQO), which were developed from this uncertainty analysis. Results of the uncertainty analysis suggest that the combined standard uncertainty in ammonia emission from broiler houses in the study was typically less than 6%; it increased with uncertainty in ventilation rate, but decreased as ventilation rate and number of fans running increased. The combined standard uncertainty was quantified for normal measurement conditions (Case 1) and for conditions in which the instrumentation was at the calibration threshold (Case 2). A key conclusion was that, for the measurement system employed in this project, uncertainty in the measurements associated with ventilation rate are the major contributors to emissions rate uncertainty (ranging from 78% to 98.9% of combined standard emission uncertainty). [ABSTRACT FROM AUTHOR]

Hoop structures have been used quite widely for animal production in the U.S. due to their lower capital costs and multi-purpose versatility. Hoop barns for grower-finisher (G-F) swine production have attracted attention in China as an alternative, environmentally friendly, and water-saving production system. This study was conducted to assess concentrations and emissions of ammonia (NH3) and greenhouse gases (GHGs) for a hoop G-F pig barn at a commercial pig operation in suburban Beijing, China. The NH3 and GHG concentrations and emissions of the facility were measured for three consecutive days during spring and summer seasons. The results revealed the following hourly gaseous concentrations (mean ± SD, mg m-3): 5.9 ± 2.7 NH3, 2,183 ± 1,376 CO2, and 4.0 ± 2.5 CH4 in spring, and 6.8 ± 3.4 NH3, 1,530 ± 364 CO2, and 5.0 ± 2.3 CH4 in summer. The estimated gaseous emissions averaged, in g pig-1 d-1, 22.7 NH3, 2,003 CO2, and 6.7 CH4, or in g AU-1 d-1 (AU = 500 kg), 124 NH3, 11,264 CO2, and 36.2 CH4. The emission values from this study, while being generally comparable with those reported in the literature, add new information concerning emissions from alternative swine housing system. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) emissions from broiler houses have been monitored almost exclusively while the house is populated with live birds. Many American growers utilize litter for more than one flock. Between flocks, various litter management practices are used to prepare this "built-up" litter for the next flock, including some degree of house ventilation to keep the indoor ammonia concentration low. Ammonia volatilized from the litter is emitted to the environment during the downtime. This ammonia emission should be accounted for in the determination of a facility's annual ammonia emission inventory. In the study reported here, ammonia emissions were monitored from two recently depopulated broiler houses in Pennsylvania using built-up litter managed for five consecutive flocks. Average house air temperature during the monitoring period was 10.2 °C, well below the typical temperature during flock production. Emission was calculated whenever a house exhaust fan was running. The results revealed ammonia emissions from the houses ranging from 212 to 1107 g h-1. The daily emission rate (ER) was highest on day 2, coinciding with the first harrowing of the litter, and then decreased over subsequent days. These average values during downtime were about one-quarter of the ER values for market-size birds observed during flock grow-out in the same houses over the previous year. The reduced ER during the cleanout period was anticipated, since the built-up litter was at a lower temperature than during grow-out and there was no further fresh manure addition contributing to potential ammonia volatilization. Observed variation between these two houses with identical management and construction showed that monitoring a single house may not accurately predict empty house emissions, with unidentified factors other than management being responsible for this variability. [ABSTRACT FROM AUTHOR]

Emissions of greenhouse gases (GHGs) from animal feeding operations to the atmosphere are of environmental importance and concerns because of their impact on global warming. Gaseous concentrations and emission rates (ERs) of animal facilities can be affected by the animal production stages, animal species, dietary nutrition, housing types, manure handling schemes, and environmental conditions. This article reports ERs of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) for a typical, naturally ventilated 24-crate swine farrowing barn located in suburban Beijing, China, that was monitored over one-year period. The measurements were made at bi-monthly intervals (i.e., six measurement episodes total), with each measurement episode covering three consecutive days. Gaseous concentrations were monitored at bi-hourly intervals throughout each 3-day measurement episode. The ventilation rate of the barn was estimated using the CO2 mass balance method. The GHG concentrations and ERs of the farrowing barn showed diurnal and seasonal variations. Specifically, the concentrations (monthly mean ± SD, mg m-3) ranged from 2.3 (±0.3) to 9.3 (±2) for CH4, from 0.6 (±0.02) to 1.2 (±0.16) for N2O, and from 1, 370 (±163) to 11,100 (±950) for CO2, with the higher levels occurring in January and the lower levels in July. The specific ER ranged from 95.2 to 261.8 mg h-1 pig-1 for CH4, from 6.4 to 12.9 mg h-1 pig-1 for N2O, and from 122.9 to 127.3 g h-1 pig-1 for CO2 . On the basis of per animal unit (1 AU = 500 kg live body mass), the average daily ERs of the farrowing barn were 9.6 ± 3.6 g AU-1 d-1 for CH4, 0.54 ± 0.15 g AU-1 d-1 for N2O, and 7.5±0.1 kg AU-1 d-1 for CO-2. Results of the GHG ERs from this study differ markedly from the limited literature data collected primarily under European production systems and conditions. Results of the current study provide some baseline data on GHG ERs for swine farrowing operations, thus contributing to development or improvement of GHG emission inventory under the Chinese livestock production conditions. [ABSTRACT FROM AUTHOR]

Twelve commercial broiler houses in the U.S. were each monitored for at least thirteen 48 h periods over the course of one year to obtain ammonia emission data. Paired repetition of houses on four farms represents current construction with variety in litter management (built-up or new litter each flock) and climate conditions (cold or mixed-humid). Ammonia concentration was determined using portable electrochemical sensors incorporating a fresh air purge cycle. Ventilation rate was determined via in-situ measurement of fan capacity, fan on-off times, and house static pressure difference. There were seasonal trends in exhaust ammonia concentration (highest in cold weather) and ventilation rates (highest in warm weather) but not for emission rate. Flocks with at least three monitoring periods (13 of 22 flocks) demonstrated similar emission rates at a given bird age among the four study farms and across the seasons. An analysis of emissions from all houses on the three farms using built-up litter resulted in predicted regression slopes of 0.028, 0.034, and 0.038 g NH3 bird-1 d-1 per day of age; the fourth farm, managed with new litter, had the lowest emission rate at 0.024 g NH3 bird- 1 d-1. The intercept of these composite relationships was influenced by litter conditions, with flocks on new litter having essentially no emissions for about six days while built-up litter flocks had emissions starting at flock placement. Data from all four farms and all flocks provided a regression slope of 0.031 (±0.001 std error) g NH3 bird-1 d-1 per day of age. Emission rate per animal unit for built-up litter flocks indicated very high emissions for the youngest birds (under 14 days of age), after which time the emissions decreased exponentially and were then relatively steady for the balance of the flock cycle. [ABSTRACT FROM AUTHOR]