Slatted Floor Systems Research Articles

Winter housing systems and costs of sheep production in Norway

Housing and indoor feeding of sheep is required throughout the cold season, which can last more than half a year, in Nordic highlands and Alpine regions. This study aimed to examine and evaluate the housing costs, including labour requirements, according to type of sheep housing system and degree of mechanized feeding by investigating systems commonly used in Nordic and Alpine regions. Detailed cost data were obtained from 61 surveyed sheep farmers in Norway with sheep houses built between the years 2008 and 2015. Costs were calculated for a baseline scenario (2021-prices) as well as for five scenarios at low and high discount rates and opportunity cost of labour, and high energy prices. The median (interquartile range) flock size was 150 (100) winter-fed sheep. Houses with slatted floors were more expensive than deep-litter systems. Costs of bedding material and feed waste were however higher, and the net value of the manure were lower in houses with deep-litter systems. At the baseline assumptions, overall net housing costs per sheep was not statistically different among the main housing types studied. Multiple regression analyses showed that net housing costs per sheep were lower in larger flocks and for centrally located farms (control variables). Undertaking daily chores, such as feeding of roughages twice a day rather than once, resulted in significantly higher net housing costs. Mechanized feeding of roughages, and even more so for concentrates, were not economically justified since labour savings were not sufficient to pay for the additional capital costs. A round bale chopper lowered net housing costs, significantly at a high labour cost. None of the scenarios found slatted floors to be significantly more expensive than deep-litter systems. High costs of labour and capital favoured deep-litter systems, while slatted floor systems were more advantageous at rising prices of energy that resulted in increased values of organic manures and costs of feed wastes and bedding materials. The study was based on a decade old data from common Norwegian sheep house variants. Farmers that consider constructing a new sheep house today, still must compare these variants as their main alternatives. We encourage other researchers to include effects of housing systems and mechanized feeding on animal performance, health, and welfare. Moreover, future studies should preferably also be undertaken in other environmental or socio-economic settings to produce more general results.

Applicability evaluation of innovative simplified methods of slatted floor in pig houses – A CFD study

The slatted floor system is often used in pig housing. Computational Fluid Dynamics (CFD) is a valuable technique for determining the airflow and gas dispersion within the pit headspace through the slatted floor. However, there is a practical issue related to modeling the thousands of small slot openings in real livestock buildings for CFD simulation. It is unpractical to simulate the slatted floor with geometry details due to the large mesh number and the limited computer capacity. In this study, several methods to simplify the model of the slatted floor were explored to reduce the computational cost. The study was based on CFD analysis supported by experimental validation. The slatted floor was modeled in four ways: direct geometry method (DGM), porous-region method (POM), and profiled-porous-region method (including PPOM-cell (PPOM-C) and PPOM-floor (PPOM-F)). To assess the feasibility of the simplification, the four modeling approaches were compared with the experimental data. The results showed that it’s feasible to model the slatted floor as POM or PPOM. The accuracy of POM was high, but it was greatly affected by the calculation of the resistance coefficient. PPOM-C has greatly reduced the amount of calculation, which could be used to simplify the large-scale pig house model whose flow fields and gas emissions below the slatted floor could be ignored. The simulation result of PPOM-F was the closest to DGM, however, due to the large number of meshes and complex setup, it was not suitable for practical simulation.

The Effects of Partially Slatted Floor Designs on Some Early Behavioral Traits in Broiler Chicks

This study was carried out to determine the effects of different levels of slatted floor applications on some early behavioral characteristics of broiler chickens. In this study, male-female mixed 600 fast-growing broiler chicks (Ross308) were used. The experiment consisted of five treatment groups with 120 chicks each (7 chicks/m2): fully littered, fully slatted, ½ littered+½ slatted, 1/3 littered+2/3 slatted, 2/3 littered+1/3 slatted. In the study, the feeding, drinking, resting, aggregation, other behaviors, and slatted floor preferences of the chicks were evaluated three times a day (at 9.00, 13.00, and 17.00 h) at 2, 5, 9 and 11 days of age. Each behavioral trait was expressed as a percentage of the total number of chicks showing the relevant behavior at the pen level. Different floor designs significantly affected the chicks' feeding, resting, aggregation behavior, and preference for being on the slatted floor (P < 0.05). Feeding behavior was higher in chicks reared on the fully slatted floor than in the others (P < 0.001). The percentage of chicks showing resting behavior was highest in the 2/3 littered+1/3 slatted floor application (P = 0.001). The 64.42% of the chicks reared in 2/3 slatted, 47.53% of those reared in ½ slatted, and 36.38% of those raised in 1/3 slatted preferred the use of the slatted floor. The percentage of chicks showing feeding behavior was highest at 5 (16.12%) and 2 d-old (15.73%) (P = 0.001). Resting behavior was highest at 2 (78.72%), 5 (76.89%), and 9 (72.82%) days of age (P < 0.001). In conclusion, this study revealed that different floor designs affect some behavioral characteristics in the early chick period. Since it is known that early rearing conditions affect later performance in broilers, slatted floor systems with higher feeding behavior can be an effective tool for better performance in broiler production.

Comparison of Methane Emission Patterns from Dairy Housings with Solid and Slatted Floors at Two Locations

Methane (CH4) emissions from dairy husbandry are a hot topic in the context of active climate protection, where housing systems with slatted floors and slurry storage inside are in general expected to emit more than systems with solid floors. There are multiple factors, including climate conditions, that modulate the emission pattern. In this study, we investigated interrelations between CH4 emission patterns and climate conditions as well as differences between farm locations versus floor effects. We considered three data sets with 265, 264 and 275 hourly emission values from two housing systems (one slatted, one solid floor) in Switzerland and one system with solid floors in Germany. Each data set incorporated measurements in summer, winter and a transition season. The average CH4 emission was highest for the slatted floor system. For the solid floor systems, CH4 emissions at the Swiss location were around 30% higher compared to the German location. The shape of the distributions for the two solid floor systems was rather similar but very different from the distribution for the slatted floor system, which showed higher prevalence for extreme emissions. Rank correlations, which measure the degree of similarity between two rankings in terms of linear relation, were not able to detect dependencies at the selected significance level. In contrast, mutual information, which measures more general statistical dependencies in terms of shared information, revealed highly significant dependencies for almost all variable pairs. The weakest statistical relation was found between winds speed and CH4 emission, but the convection regime was found to play a key role. Clustering was consistent among the three data sets with five typical clusters related to high/low temperature and wind speed, respectively, as well as in some cases to morning and evening hours. Our analysis showed that despite the disparate and often insignificant correlation between environmental variables and CH4 emission, there is a strong relation between both, which shapes the emission pattern in many aspects much more in addition to differences in the floor type. Although a clear distinction of high and low emission condition clusters based on the selected environmental variables was not possible, trends were clearly visible. Further research with larger data sets is advisable to verify the detected trends and enable prognoses for husbandry systems under different climate conditions.

Estimation of ammonia emissions from a dairy farm using a computer program

Ammonia emission tests were carried out on a dairy cow farm (100 large production units) with a slatted-floor system. The air for the tests was collected into gas washing bottles. Ammonia emissions were modeled using Operat FB software. The enthalpy of the process and the molar mass of the oxidized substance were used to calculate the calorific value of gases on the farm. The highest ammonia concentrations on the farm were obtained in the autumn and winter and amounted to 11.2 mg/m3. The highest mass of this gas in the modelling, defined as the maximum emission, was 0.85 kg/h. The annual emission was estimated at 2.78 Mg/year. These results were the basis for estimating the amount of energy (0.85 kg/h) obtainable from ammonia on the farm. The modeling of ammonia emissions applied in the study can be used to calculate the potential degree of pollution introduced into the environment and to estimate the degree of pollutants reduction.Ammonia from the farm, together with the methane emitted, can be catalytically oxidized as a potential energy source.

Effects of Different Floor Systems and the Bird’s Age on Body Weight Gain and Feather Score of Broiler Breeder Hens

Purpose: Feathers are known to play a significant role in thermoregulation and provide a physical protection to the birds. Presence or absence of a good feather cover therefore, directly influences on a bird’s performance. The study reported herein was conducted to assess the effects of floor system and the bird’s age on body weight gain (BWG) and feather score in Indian River (IR) broiler breeder hens. Research Method: The experiment was conducted in 2 x 4 factorial arrangements of treatments which included two floor systems (slatted floor and litter floor) and four age groups (23, 32, 38 and 45 weeks). A total of 400 IR breeder hens were assigned to 08 treatments with two replicates per each (25 birds/replicate) and were fed formulated breeder rations recommended based on the age and the production rate. The body weight, mortality and feather scores were recorded in a two-week experimental period. Findings: A significant interaction (P<0.05) between floor type and age was observed for BWG. The highest mean BWG was recorded (313 g/bird) in 23-week old birds kept on slatted floors. Overall feather loss (P<0.05) and feather loss in back (P<0.05), wings (P<0.05) and tail areas (P<0.05) of IR breeder hens were the lowest when the birds were kept on slatted floors. Increasing bird’s age significantly (P<0.05) increased the overall feather loss and feather loss in back, wings and tail areas. Original Value: The present study concluded that among the age groups tested, the highest BWG of IR breeder hens were recorded at 23-weeks of age when they were on slatted floors. The slatted floor system was highly effective in reducing feather loss in IR breeder hens. Feather loss was increased with advancement of a bird’s age.

Occurrence of flea infestation on goats under stall fed condition and its control.

A total 1862 goats from 12 stall fed goat farms under slatted floor system were examined for the presence flea infestation in six districts of Tamil Nadu. Overall prevalence of flea infestation on goat was 30.79% of which, 72.73 and 27.27% were Ctenocephalides orientis and C. felis respectively. Out of these 12 farms, heavy flea infestation was noticed on goats which were reared on slatted floor with dung on floor, where as the goats that were reared on the clean shed (without dung on the floor) were free from flea infestation. In human beings first time flea bite exposure showed erythematous patches and partially healed erythematous patch with irregular crusts. Efficacy of flumethrin (pour-on) and deltamethrin (dipping) was carried out in 30 kids. Of these, deltamethrin controlled the flea within a day after application whereas, flumethrin controlled the flea after 2-3 days of application.

The effects of slatted floors and manure scraper systems on the concentrations and emission rates of ammonia, methane and carbon dioxide in goat buildings

This study was designed to quantify the concentrations and emission rates of ammonia (NH3), methane (CH4) and carbon dioxide (CO2) and to evaluate their effects on the indoor environment of slatted floor and manure scraper systems in two goat buildings. One building had a slatted floor and a manure scraper system (building II); the other building did not, and manure removal was performed by workers (building I). This study was conducted from April 2014 until January 2015, with sampling during four seasons. The NH3, CH4 and CO2 emission rates were highest in the summer and lowest in the winter in both buildings. However, in building II, these emission rates were significantly lower (P<0.05) than those in building I in each season. In both buildings, the NH3, CH4 and CO2 concentrations were highest in the winter and lowest in the summer, although the gas concentrations were significantly lower (P<0.05) in building II than in building I. The results of this study suggest that the slatted floor and manure scraper systems substantially lower the emissions of harmful gases in goat buildings.

Numerical modelling of airflow and gas dispersion in the pit headspace via slatted floor: Comparison of two modelling approaches

The slatted floor system is popular in pig and cattle housing. Ammonia and odour are mostly emitted from the slurry pit under the slatted floor. In order to develop solutions to reduce this part of emissions, a better understanding of air distribution and pollutant transportation mechanisms is required. Computational fluid dynamics (CFD) is a useful technique to investigate the air motion, and transport of pollutants between room and pit headspaces via the slatted floor. However, there is a practical issue related to modelling the thousands of small slot openings in the real livestock building for CFD simulation. It is unrealistic to simulate the slatted floor with geometry details due to the large grid number and the limited computer capacity. In this study, a simplification model using porous media to represent a scaled slatted floor was developed. To assess the feasibility of this simplification, the proposed porous media model (SP) was compared with the direct geometry model (SD) and experimental data. The results showed that the porous media model was able to estimate the air velocities but not the turbulent kinetic energy. Both models predicted rotating flows under the slatted floor. A clear vertical air motion above the slatted floor was found for SP results but no such trend for SD results. The mechanism of the pollutant transportation, including the process of pollutant escaping from the pit and retention time of pollutant inside the pit headspace, was found to be inconsistent for SD and SP models. For SD, the dominant removal mechanism of transporting pollutants from the headspace to the free stream was mean flow transportation whereas it was turbulent flow transportation in SP. Higher emission rate and shorter retention time of pollutant in the headspace was obtained by using SP compared to SD. In general, though the porous media approach cannot reveal the pollutant transport mechanism, it can predict the velocity magnitude. In addition, it was found that the orientation of slats to stream flow direction plays an important role on airflow pattern and pollutant distribution inside the pit headspace.

Influence of permanent use of feeding stalls as living area on ammonia and greenhouse gas emissions for group-housed gestating sows kept on straw deep-litter

In pig production, the interest for litter systems in relation with animal welfare and the ban by 2013 in the EU of individual accommodations for gestating sows could promote the group-housing of gestating sows on deep-litter. However, compared to slatted-floor systems, few data are available on the gaseous emissions associated with the different modalities of rearing sows on deep-litter. In this study, two modalities were compared: group housing on a 3m2/sow deep-litter or on a 1.8m2/sow deep-litter plus 1.2m2/sow concrete floor. In both cases, sows were fed in individual feeding stalls (1.2m2/stall) but the access was limited at feeding time in the first case and permanent in the second one.Three successive batches of 10 gestating sows were used. Each batch was divided into 2 homogeneous groups randomly allocated to one of two treatments: fully (3m2/sow) or partly (1.8m2/sow) straw-based deep-bedded floor. The groups were kept separately in two identical rooms with same volume and same surface, equipped with five individual feeding stalls in contact with a pen of either 9 or 15m2 deep-litter. The feeding stalls were equipped with front feeding troughs and rear gates allowing or not permanent access to the stalls outside of feeding times. Between each batch, the pens were cleaned. In both rooms, ventilation was automatically adapted to maintain a constant ambient temperature. The gas emissions (nitrous oxide, methane, carbon dioxide, ammonia and water vapour) were measured 3 times (weeks 2, 5 and 8 of stay) during 6 consecutive days by infrared photoacoustic detection.Sow performance was not significantly affected by floor type. With sows kept on partly bedded floor, gaseous emissions were significantly greater for methane (12.76 vs. 9.90g/d.sow; P<0.001), carbon dioxide (3.12 vs. 2.90kg/d.sow; P<0.01) and water vapour (4.70 vs. 4.03kg/d.sow; P<0.001), and significantly lower for nitrous oxide (3.14 vs. 6.12g/d.sow; P<0.001) and CO2 equivalents (1.24 vs. 2.10kg/d.sow; P<0.001) compared to sows housed on fully bedded floor. There was no significant difference for ammonia emissions (8.36 vs. 7.45g/d.sow; P>0.05).From the present trial in experimental rooms, it can be concluded that keeping group-housed gestating sows on partly straw bedded floor with permanent access to the concrete feeding stalls compared to fully straw bedded floor did not significantly influence animal performance and NH3-emissions, and decreased CO2eq-emissions (−40%). This decrease was observed owing to an important decrease of N2O-emissions (−49%).

Comparisons of two numerical approaches to simulate slatted floor of a slurry pit model – Large eddy simulations

For dairy cattle buildings with slatted floor systems, about 40% of the ammonia emission originates from the slurry pit. In order to find a solution to abate this part of emission, a better understanding of the ammonia transportation from the pit to the room space is crucial. Large eddy simulation (LES) was adopted to investigate the transportation of airflow and ammonia under slatted floor. To tackle the involvement of the slatted floor, two approaches were proposed: modelling slatted floors directly with geometrical details (LESD) and treating them as porous media (LESP). The main purpose of this work was to study the potential of using porous media to model the slatted floor. The LES results were validated by the air velocities measured using a LDA (Laser Doppler Anemometer) in a 1:8 scale pit model placed in a wind tunnel. The results showed that LESP was able to estimate the mean air velocities and turbulence kinetic energy in the core of the pit headspace; but it cannot well predict the mean air velocities and turbulence kinetic energy in the space next to the upwind wall. Clear vertical air motion in the top surface of the slot was observed for LESD results. There was not such trend found for LESP results. Both the air velocity and NH3 fraction fluctuated weaker for LESP results. By spectral analysis, LESP was able to capture the entire power spectrum compared with LESD. A dominant Strouhal number 0.23 was found for LESD results but no dominant Strouhal number was found for LESP results. The emission rate and total mass of NH3 in the pit headspace calculated by LESD was double of those calculated by LESP. Pollutants were confined in the headspace for longer time by means of using LESP than using LESD. For both LESD and LESP, turbulence transportation was the dominant removal mechanism to transport pollutants from the headspace to the free stream.

Monitoring of Emission of Ammonia, Hydrogen Sulfide, Nitrogen Oxide and Carbon Dioxide from Pig House

The aim of this study was to determine the concentration level of ammonia (NH3), nitrous oxide (N2O), hydrogen sulfide (H2S), and carbon dioxide (CO2) in two different fattening pig houses operated with slatted floor and straw flow system. The field study was performed for three day. One large-scale pig house with capacity of 230 pigs operate with deep litter manure system under the fully slatted floor and one small-scale pig feeding operation with capacity of 200 pigs operated by scraper and straw flow system, located at the Iksan city, South Korea, were investigated in this study. Average emissions of gases on the slatted floor pig house measured were 59.8-70.5 ppm NH3, 0.048-0.78 ppm H2S, 453.1-650.8 ppm CO2 and 0.21-0.68 ppm N2O while the concentrations of these gases at straw flow pig house were determined as 28.17-42.53 ppm NH3, 0.11-0.43 ppm N2O, 0.018-0.043 ppm H2S, 400.2-498.3 ppm CO2. In general, result of H2S, CO2, N2O and NH3 emissions from the straw flow system were lower than values for fully slatted floor systems.

An assessment of a partial pit ventilation system to reduce emission under slatted floor – Part 2: Feasibility of CFD prediction using RANS turbulence models

CFD simulations were carried out to assess the feasibility of using RANS (Reynolds – averaged Navier–Stokes) turbulence models to evaluate the performance of a partial pit ventilation system to reduce gas emission under slatted floor. The entire system included a pit model with slatted floor and pit exhaust system, a wind table to simulate ground and a wind tunnel to simulate room space of a naturally ventilated livestock house. CFD simulations started with the selection of a proper domain. Two domains were chosen to evaluate the effect of domain simplification. The results showed that the effect was significant. The assessment of different turbulence models including the standard, RNG, realizable k-ε models; transition SST k-ω model; Reynolds Stress Models were conducted. Results of RSM were found out to agree best with measured results. In order to understand the transportation mechanism of pollutant through slatted floor, vertical mean and turbulent flux were defined and calculated. It was found that turbulence diffusion dominates the transportation of pollutant from the pit headspace into the free stream. Although discrepancies existed for some conditions, good agreements of measured and calculated removal ratios were found for most of cases. It was feasible to use RSM to predict the removal capability.The future research should focus on depicting the airflow patterns inside the pit by using scale model under well controlled laboratory conditions and generating benchmark data to validate and improve CFD methods. Unsteady CFD simulation using large eddy simulation could be conducted to make more precise predictions of removal capability of the partial pit ventilation system by considering the unsteady phenomena of gas emission.

Ammonia and odour emitted from deep litter and fully slatted floor systems for growing-finishing pigs

Two identical pig rooms, with mechanical ventilation, were used to compare the environmental impact of a deep litter fermentation system for growing-finishing pigs with a fully slatted floor system. The pig manure in the fully slatted floor room was removed manually twice daily, but in the fermented deep litter room, no manure was removed. Indoor and outdoor temperature, relative humidity, and ammonia concentration were measured continuously during the whole experimental period. Odour was sampled and analysed using the triangle odour bag method for 15 days during the experimental period. The performance of the pigs was not significantly different between the floor types. There were significant differences for both NH3 concentrations and emissions according to floor type (p It was concluded that the deep litter fermentation system for pig production shows advantages in reductions of ammonia and odour.

Gaseous emissions from weaned pigs raised on different floor systems

Gaseous emissions from agriculture contribute to a number of environmental effects. Carbon dioxide (CO 2), methane (CH 4) and nitrous oxide (N 2O) are greenhouse gases taking part to the global problem of climate change. Ammonia (NH 3) emissions are responsible of soil acidification and eutrophication and contribute also to indirect emissions of N 2O. This work evaluated the influence of the type of floor on the emissions of these gases in the raising of weaned pigs. Two trials were carried out. In the first trial, the animals were kept either on fully slatted floor or on straw-based deep litter and, in the second one, either on fully slatted floor or on sawdust-based deep litter. For each trial and on each type of floor, 2 successive batches of weaned pigs were raised without changing the litter or emptying the slurry pit between the 2 batches. The rooms were automatically ventilated to maintain a constant ambient temperature. The performance of the animals was not significantly different according to the floor type. In trial 1, the nitrogen contents of the straw deep litter (including the substrate) and slurry were respectively 276 and 389 g pig −1. In trial 2, the sawdust deep litter and slurry nitrogen contents were respectively 122 and 318 g pig −1. Raising pigs on straw deep litter produced proportionately around 100% more NH 3 than raising pigs on slatted floor (0.61 g NH 3-N d −1 pig −1 vs. 0.31 g NH 3-N d −1 pig −1; P < 0.05). Differences in CO 2, H 2O and CH 4 emissions were not significant between systems. Raising pigs on sawdust deep litter produced also proportionately more NH 3 (+52%; 0.55 g NH 3-N d −1 pig −1 vs. 0.36 g NH 3-N d −1 pig −1; P < 0.01) but also more CO 2 (+25%; 427 g d −1 pig −1 vs. 341 g d −1 pig −1; P < 0.001) and H 2O (+65%; 981 g d −1 pig −1 vs. 593 g d −1 pig −1; P < 0.001) and less CH 4 (−40%; 0.52 g d −1 pig −1 vs. 0.86 g d −1 pig −1; P < 0.001) than raising pigs on slatted floor. Practically no N 2O emission was observed from rooms with slatted floor while the N 2O emissions were 0.03 and 0.32 g N 2O-N d −1 pig −1 for the straw and sawdust deep litter respectively. The warming potential of the greenhouse gases (N 2O + CH 4), were about 22, 34 and 168 g CO 2 equivalents per day and per pig on fully slatted floor, straw or sawdust deep litter respectively. In conclusion, pollutant gas emissions from rearing of weaned pig seem lower with fully slatted plastic floor system than with deep litter systems.

Ammonia and greenhouse gas emissions from a straw flow system for fattening pigs: Housing and manure storage

Animal welfare and environmental protection are increasingly important. Housing systems must be found that offer animal welfare while minimizing the overall emissions of ammonia and greenhouse gases. The straw flow system is an animal friendly housing system for fattening pigs, which can be operated economically on commercial farms. Emissions from conventional slurry based pig houses have been intensively studied, but more research is needed into straw based systems. In this study, we quantified emissions of ammonia and greenhouse gases from a straw flow system with or without daily removal of slurry to an outside store. The effect of applying a solid cover during outside storage was also examined. Emissions of NH 3, N 2O, CH 4, and volatile organic C (VOC) from a commercial straw flow system for fattening pigs in Upper Austria were measured between June 2003 and March 2004. Emissions of CH 4 during housing were 1.24 and 0.54 kg CH 4 per pig place per year without and with daily manure removal, respectively. The corresponding N 2O emissions amounted to 39.9 and 24.5 g N 2O per pig place per year, and NH 3 emissions to 2.10 and 1.90 kg NH 3 per pig place per year without and with daily manure removal. Emissions of CH 4, N 2O and NH 3, and of total greenhouse gases, from the straw flow system were lower than literature reference values for forced ventilated fully slatted floor systems. Daily removal of the manure to an outside store reduced emissions from the pig house. Emissions during storage of pig slurry derived from a straw flow system were quantified between June 2004 and June 2005. Slurry was stored in pilot scale stores with or without a solid cover and emissions quantified by a large open dynamic chamber. The solid cover reduced NH 3 and greenhouse gas emissions by 30 and 50%, respectively. During cold climatic conditions stored pig manure emitted less NH 3 and greenhouse gases than when stored under warm climatic conditions. We recommend the use of separate emission factors for slurry storage in the colder and warmer periods in the national emission inventory, and the use of covers on pig slurry stores. Overall, it is concluded that the straw flow system may combine recommendations of animal welfare and environmental protection.

A concrete slatted floor system for separation of faeces and urine in pig houses

A concrete slatted floor system that consists of a narrow-gap slatted floor and beneath it a slope bottom for separation of faeces and urine in pig houses was investigated. In the experiments, four concrete slatted floors with one of two slat profiles and one of two gap widths, and a steel wire slatted floor were studied to estimate their manure separation performance under practical conditions. To evaluate urine collection efficiency, seven slope gradients and two surface roughnesses of the slope bottom were investigated under laboratory conditions. The lowest percentage of faeces drainage (0.36%) and good urine drainage performance were obtained by a concrete slatted floor with 5 mm-wide gaps and a trapezoidal profile without sharp edges, indicating that separation of faeces and urine can be achieved on the surface of this slatted floor. Using the wet surface area of the slope bottom as an indicator of urine collection efficiency and emission source, a statistical model was developed based on slope gradient, surface roughness, amount of water and water drop height. It was found that the wet surface area of the slope bottom decreased as the slope gradient increased, but increased with increasing surface roughness. The wet surface area was much more sensitive to the variations of slope gradient at lower compared with higher gradient ranges. However, contrary sensitivity responses were obtained for surface roughness. A slope gradient of 20° with a surface coated with fine cement performed best and is recommended for the slope bottom design in the concrete slatted floor system.

Gaseous emissions during the fattening of pigs kept either on fully slatted floors or on straw flow

The aim of this study was to compare the environmental impact of the straw-flow system for fattening pigs with the slatted-floor system by measuring pollutant gas emissions such as ammonia (NH3), nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2), manure nitrogen (N) content and emissions of water vapour (H2O). Three successive batches of 32 pigs were fattened. For each batch, pigs were allotted to two groups raised in separated rooms fitted either with a concrete totally slatted-floor system (0.75 m2 per pig) or with a straw-flow system (0.79 m2 per pig). With this last system, pigs were kept on a sloped floor, straw being provided daily at the top of the pen. Throughout the fattening period, about 34.4 kg of straw were supplied per pig. The straw, mixed with dung, travelled down the slope by pig motion and went out of the pen to a scraped passage. The solid fraction was scraped every day, stored in a heap in the room and removed every month, 1 week before each period of gaseous emission measurement. The liquid fraction was automatically pumped from the scraped passage into a hermetic tank, which was emptied at the end of each fattening period. Rooms were ventilated mechanically in order to maintain a constant ambient temperature. Once a month, the emissions of NH3, N2O, CH4, CO2 and H2O were measured hourly for 6 consecutive days via infrared photoacoustic detection. Mean daily emissions per pig fattened on the slatted floor or on the sloped floor were, respectively, 4.98 and 13.31 g NH3, 0.67 and 0.68 g N2O, 15.2 and 8.88 g CH4, 548 g and 406 g CO2 equivalents, 1.61 and 1.77 kg CO2 and 2.33 and 2.95 kg H2O. Except for N2O emissions, all the differences were statistically significant (P < 0.001). From the slatted-floor system, the amount of slurry removed per fattening period was on average 256 kg per pig. From the straw-flow system, solid manure amounted on average to 209 kg per pig and liquid manure to 53 kg per pig. The total N-content of the manure was 2.23 kg N per pig with the straw-flow system (solid and liquid manure) v. 3.26 kg N per pig for slurry from the slatted-floor system. This reduction of 30% observed with the sloped floor was mainly explained by the higher level of NH3-N emissions.

Ammonia and greenhouse gas emissions from a straw flow system for fattening pigs

The straw flow system is an animal friendly housing system for fattening pigs. The pen is separated into a lying area, where straw is used, and an excretion area. The pigs keep the lying area dry and clean and excrete on slats in the rear of the pen. The system can be operated economically efficient on commercial farms. It was to be investigated, if this animal friendly housing system emitted less NH 3 and GHG than a conventional fully slatted floor system. Emissions of NH 3, N 2O, and CH 4 were measured at a commercial farm for 10 months. Measurements covered all seasons and all stages of fattening. Emissions from the straw flow system were always lower than default values for fully slatted floor systems.

NH3-, N2O- und CH4-Emissionen aus einem Schrägbodenstall für Mastschweine

The straw flow system is an animal friendly and functioning housing system for fattening pigs. Greenhouse gas and ammonia emissions from a commercial straw flow system were continuously measured from June 2003 to April 2004. Emissions were always lower than the default values of forced ventilated fully slatted floor systems. The straw flow system combines animal welfare and environmental protection.