The environmental impact and potential public health impacts of naturally ventilated pig barns with outdoor exercise yards are less well studied compared to conventional intensive housing systems. The aim of this paper was to investigate the characteristics of airflow and gaseous emissions from an outdoor exercise yard in a naturally ventilated pig barn, and the impact of the barn emissions on the surrounding environment. The investigations were carried out using a 1:50 scaled pig barn model with different inlet opening sizes and roof structures in a large atmospheric boundary layer wind tunnel. Air velocities at the emission active surface, as well as air velocities and tracer gas concentrations at four planes downwind of the barn model were measured using a 2-dimensional Laser Doppler Anemometer and a Fast Response Flame Ionisation Detector system. It was found that the opening size and roof structure had a large impact on the airflow patterns and thus on the gas dispersion. The airflow measurement results demonstrated that the pig barn with small openings especially those without roof over the outdoor yard might have less environmental impact on the surroundings. This study contributed to a detailed understanding of airflow and dispersion characteristics downwind the pig barn and provided insights for structural design of similar pig barns aiming to mitigate their environmental impacts.

To address the growing demand for environmental and animal-friendly housing with outdoor space, there is a need for reliable techniques to quantify gaseous emissions. However, there is limited research on measurement methods to determine gaseous emissions from these housing systems. Therefore, this study focuses on developing measurement techniques to assess gaseous emissions from a novel concept of a welfare-friendly pig housing system with an outdoor run in the Netherlands. This concept employs measures like an optimal pen design and a daily excreta removal system where urine and faeces are directly separated. Within this concept new-born piglets stay in the same pen until slaughter weight is reached, promoting better excretion behaviour. The outdoor yard is designed with both slatted and solid flooring, aiding pigs in distinguishing between excretion and lying areas. This design feature is intended to contribute to the reduction of emissions and enhance animal welfare. In the current study, to measure emissions and assess the potential for emission reduction, diverse techniques are outlined. Measurements are conducted at both barn and pen levels, employing the micro-meteorological technique coupled with inverse dispersion modeling, and N (and P/K) balance methods at the barn level. The micro-meteorological method measures gas concentrations upwind and downwind as well as the wind parameters, utilizing a modelling approach, i.e. the backward Lagrangian stochastic model, emission rates are computed. The N (and P/K) balance method estimates nitrogen emissions by measuring inputs, animal discharge, and nitrogen content in feces and urine during a balance period. At the pen level, local measurements are conducted to identify sources of ammonia emissions and quantify the emissions from the surface source by using an enclosure method, the fast box measurement system. The urine composition of all pig categories is assessed for NH4-N and urea-N content, as well as pH, through the collection of fresh urine. Urease activity on the solid floor inside and outside the pig house is determined using standard methods. Ammonia emissions from the urine-contaminated solid floor and solid floor with straw are measured at various temperatures and air velocities in the measurement box. Additionally, the urine-soiled area of the inside and outside solid floor, along with the frequency of urine discharges in different locations of the pen is determined using (heat) cameras. This information is then utilized to calculate ammonia emissions through an existing model. The study comprises two phases: development and optimization, followed by implementation. Overall, this research aims to formulate a protocol for emission measurements and determination of the emission factors, contributing to a more comprehensive understanding of emissions from pig housing systems with an outdoor run, and promoting more sustainable and eco-friendly housing systems.

With an ongoing transition towards the use of Light Emitting Diodes (LED), more knowledge is needed on which light settings optimise sustainability parameters in pig production. We studied effects of four light intensities on social, environmental and economic sustainability indicators, including ammonia emissions, space use, pen fouling, weight gain, carcass quality, perception of the stockkeeper, costs of the light system, and use of drinking water, electricity and medicines. Light treatments included a low (45 lux), medium (198 lux) and high (968 lux) uniform intensity, and a spatial gradient treatment ranging from 71 lux in the front to 330 lux in the back of each pen. The latter treatment aimed to improve space use of functional areas. A total of 448 growing-finishing pigs were studied on a commercial farm using two consecutive batches of four rooms containing eight pens with seven pigs. Light intensity influenced some aspects of space use and pen fouling. For example, the proportion of pigs lying in the resting area was higher in the high and medium light intensity treatment than in the low intensity and gradient treatment. Moreover, the high intensity treatment resulted in more fouling with faeces in the feeding area compared with the low intensity and the gradient treatment. Ammonia emissions were higher in the gradient than in the low intensity treatment (not measured in medium and high intensity treatment). Furthermore, light intensity did not affect weight gain, carcass quality, water use and medicine use. The stockkeeper was content to work in all light conditions, but slightly preferred the medium intensity due to optimal visibility. Concerning economic performance, the costs of the light system and electricity use increased in the following order: low intensity, gradient, medium intensity, high intensity. In conclusion, contrary to expectation the spatial gradient did not notably improve space use or reduce pen fouling, but rather increased ammonia emissions in comparison with uniform light. This is likely because the gradient could not be applied in an optimal way in the existing housing conditions. Among the other sustainability indicators, mainly electricity use and costs of the light system differed per treatment. These aspects can be improved by further optimising the number of light sources needed per pen to achieve the targeted intensities.

This paper describes a model for the prediction of methane and ammonia emissions from fattening pig houses. This model was validated with continuous and discrete measurements using a reference method from two manure management systems (MMS): long storage (LS) in deep pits and short storage (SS) by daily flushing of a shallow pit with sloped walls and partial manure dilution. The average calculated methane and ammonia emissions corresponded well with the measured values. Based on the calculated and measured results, the average calculated CH4 emission (18.5 and 4.3 kg yr−1 per pig place) was in between the means from the continuous data from sensors (15.9 and 5.6 kg yr−1 per pig place) and the means from the discrete measurements using the reference method (22.0 and 3.1 kg yr−1 per pig place) for the LS and SS systems, respectively. The average calculated NH3 emission (2.6 and 1.4 kg yr−1 per pig place) corresponded well with the continuous data (2.6 and 1.2 kg yr−1 per pig place) and the discrete measurements using the reference method (2.7 and 1.0 kg yr−1 per pig place) from LS and SS, respectively. This model was able to predict the reduction potential for methane and ammonia emissions by the application of mitigation options. Furthermore, this model can be utilized as a predictive tool, enabling timely actions to be taken based on the emission prediction. The upgraded model with robust calculation rules, extensive validations, and a simplified interface can be a useful tool to assess the current situation and the impact of mitigation measures at the farm level.

Methane (CH4) emissions from manure management on livestock farms are a key source of greenhouse gas emissions in some regions and for some production systems, and the opportunities for mitigation may be significant if emissions can be adequately documented. We investigated a method for estimating CH4 emissions from liquid manure (slurry) that is based on anaerobic incubation of slurry collected from commercial farms. Methane production rates were used to derive a parameter of the Arrhenius temperature response function, lnA', representing the CH4 production potential of the slurry at the time of sampling. Results were used for parameterization of an empirical model to estimate annual emissions with daily time steps, where CH4 emissions from individual sources (barns, outside storage tanks) can be calculated separately. A monitoring program was conducted in four countries, i.e., Denmark, Sweden, Germany and the Netherlands, during a 12-month period where slurry was sampled to represent barn and outside storage on finishing pig and dairy farms. Across the four countries, lnA' was higher in pig slurry compared to cattle slurry (p < 0.01), and higher in slurry from barns compared to outside storage (p < 0.01). In a separate evaluation of the incubation method, in-vitro CH4 production rates were comparable with in-situ emissions. The results indicate that lnA' in barns increases with slurry age, probably due to growth or adaptation of the methanogenic microbial community. Using lnA' values determined experimentally, empirical models with daily time steps were constructed for finishing pig and dairy farms and used for scenario analyses. Annual emissions from pig slurry were predicted to be 2.5 times higher than those from cattle slurry. Changing the frequency of slurry export from the barn on the model pig farm from 40 to 7 d intervals reduced total annual CH4 emissions by 46 %; this effect would be much less on cattle farms with natural ventilation. In a scenario with cattle slurry, the empirical model was compared with the current IPCC methodology. The seasonal dynamics were less pronounced, and annual CH4 emissions were lower than with the current methodology, which calls for further investigations. Country-specific models for individual animal categories and point sources could be a tool for assessing CH4 emissions and mitigation potentials at farm level.

Addressing heat stress in dairy farming is a substantial challenge, and there is an increasing need for efficient cooling systems, even in regions with moderate climates. Accurately predicting the efficacy of diverse cooling options under different climatic conditions is crucial for reducing heat stress in modern high-producing dairy cows, aligning with sustainability goals. This study assessed the effectiveness and feasibility of different cooling measures, including fans, sprinklers with fans, and evaporative air cooling, using a dynamic thermoregulatory model. This 3-node dynamic model was developed based on recent animal data simulating the processes of dairy cows' physiological regulation and heat dissipation under various environmental conditions. The cooling methods were based on two principles: enhancing heat loss from cows using fans with/without sprinklers; lowering the ambient temperature by evaporative air cooling. The predicted results were discussed and partly validated using the experimental data from the literature. The predictions indicated that fan cooling alone was effective in ambient temperatures below 26 degrees C, while higher temperatures required a combination of fans and sprinklers for effective heat stress alleviation. Consideration of individual cow characteristics and environmental factors, including fan speed and wetting area, is crucial for optimal cooling. In regions with high relative humidity, evaporative air cooling could be counterproductive to some extent. The model's predictions largely aligned with experimental data, demonstrating its capability to forecast cooling effects under various climatic conditions. Future model improvements included refining calculations for water holding capacity, wetted skin area, and dry time, depending on the influence of spraying time and rate.

Due to the urgency to reduce nitrogen emissions and deposition the Dutch Ministry of Agriculture, Nature and Food Quality wants to start an investment program to stimulate the implementation of emission reducing systems in livestock production. In this report the different options for emission reduction of ammonia in pig production are given. This concerns pig houses that achieve an integral emission reduction through source-oriented measures or through a combination between source-oriented and end-of-pipe measures. This means that not only ammonia emissions should be reduced, but also emissions of greenhouse gases (particularly methane), odour and particulate matter. The reported options already have proven their efficiency to reduce ammonia emissions by protocol measurements. In this report also attention is given to emissions from manure storage systems at the farm outside the pig house and to options for reduction.

The pig industry needs strategies to solve problems such as poor rearing environment, diseases, odours, and high energy loads. In this study, an air recirculated ventilation system (ARVS) was developed with optimally designed modules and an operating algorithm. Validation experiments conducted in winter and reported here but experiments carried out during the summer and during changes in season and reported in Kim et al. (2023). Environmental data (air temperature, relative humidity, carbon dioxide, ammonia, and ventilation rate) were automatically collected during winter and livestock disease and stress of piglets were evaluated by sampling. In winter the ARVS reused internal heat energy to satisfy the pig thermal demand. Each module of ARVS modules was designed and integrated based on the previous researches. Environmental factors were monitored in real time, and then ARVS was automatically controlled using developed algorithm. The ventilation rate of the ARVS was about 3 times more than that of the conventional ventilation system (CVS). Air temperature, relative humidity, and ammonia gas inside the ARVS piglet room were optimally maintained. Also, by reusing about 73% of internal energy, it was possible to reduce heating costs. The average concentrations of ammonia and odour measured at the outlet were 2.1 ppm and 251 OU. Piglets of the ARVS weighed 1.6 kg more than those of the CVS. The disease detection rate was <1% with beneficial bacteria increased and harmful bacteria decreased. (c) 2023 IAgrE. Published by Elsevier Ltd. All rights reserved.

This report presents the results of the emission measurements that were carried out within the Klimaatenvelop 2018 (KE 2018) programme. A system that removed slurry daily out of the barn was tested for the emissions of methane, ammonia and odour on two different pig farms according to the case-control principle for finishing pigs, weaner pigs and lactating sows. The tested system is a robust system to reduce methane emissions. The measure methane reductions were even higher than pre-calculated. The pre-calculated ammonia and odour reductions have not been met, due to adaptions to the design of the systems and arising errors that occurred while managing the system.

The effects of ambient temperature (AT) on total evaporative water loss from dairy cows at different relative humidity (RH) and air velocity (AV) levels were studied. Twenty Holstein dairy cows with an average parity of 2.0 ± 0.7 and body weight of 687 ± 46 kg participated in the study. Two climate-controlled respiration chambers were used. The experimental indoor climate was programmed to follow a diurnal pattern with AT at night being 9°C lower than during the day. Night AT was gradually increased from 7 to 21°C and day AT was increased from 16°C to 30°C within an 8-d period, both with an incremental change of 2°C/d. The effect of 3 RH levels with a diurnal pattern were studied as well, with low values during the day and high values during the night: low (day, 30%; night, 50%), medium (day, 45%; night, 70%), and high (day, 60%; night, 90%). The effects of AV were studied during the daytime at 3 levels: no fan (0.1 m/s), fan at medium speed (1.0 m/s), and fan at high speed (1.5 m/s). The medium and high AV levels were only combined with medium RH. In total, there were 5 treatments with 4 replicates each. The animals had free access to feed and water. Based on the water balance principle inside the respiration chambers, the total evaporative water loss from dairy cows at a daily level was quantified by measuring the mass of water in the incoming and outgoing air, condensed water, added water from a humidifier, and evaporative water from a wet floor, drinking bowl, manure reservoir, and water bucket. Water evaporation from a sample skin area was measured with a ventilated skin box, and water evaporation, through respiration with a face mask. The results show that RH/AV levels had no significant effect on total evaporative water loss, whereas the interaction effect between RH/AV with AT was significant. Cows at a high RH had a tendency for a lower increasing rate of evaporative water loss compared with cows at a low RH (0.61 vs. 0.79 kg/d per 1°C increase of AT). Cows at medium and high AV levels had a greater increasing rate than cows at low AV (0.91 and 0.95 vs. 0.71 kg/d per 1°C increase of AT, respectively). The increase of evaporative heat loss from dairy cows was mainly a result of the increase in evaporation (of sweat) from the skin. The skin water evaporation determined with the water balance method (less evaporation from respiration) and the ventilated skin box method showed no significant difference. The implication of this study is that cows at a high AT depend mainly on evaporative cooling from the skin. The ventilated skin box method, measuring only a small part of the skin during a short period during the day, can be a convenient and accurate way to determine the total cutaneous evaporative water loss from cows.

A linear relationship between heart rate (HR) and oxygen consumption (VO2) has been reported in homeothermic animals, indicating that is possible to estimate heat production through HR measurements. This relationship may depend on the animal activity and environmental conditions. The main objective of the present study was to evaluate the effect of the air temperature and animal posture and activity on heat production and VO2 in relation to HR. In addition, as a secondary objective, the energy cost of eating and ruminating versus idling and standing versus lying down was determined. Twelve Holstein lactating cows were housed inside climate-controlled respiration chambers for 8 d, where the air temperature was gradually increased from 7 to 21°C during the night and from 16 to 30°C during the day with daily increments of 2°C for both daytime and nighttime. During the 8-d data collection period, HR and gaseous exchange measurements were performed, and animal posture and activity were recorded continuously. The oxygen pulse (O2P), which represents the amount of oxygen that is consumed by the cow per heartbeat, was calculated as the ratio between VO2 and HR. Results showed that heat production and VO2 were linearly and positively associated with HR, but this relationship largely varied between individual cows. Within the range tested, O2P was unaffected by temperature, but we detected a tendency for an interaction of O2P with the temperature range tested during the night versus during the day. This indicates that the effect of air temperature on O2P is nonlinear. Standing and eating slightly increased O2P (1.0 and 2.5%) compared with lying down and idling, respectively, whereas rumination increased O2P by 5.1% compared with idling. It was concluded that the potential bias introduced by these effects on the O2P for the application of the technique is limited. The energy cost of eating and ruminating over idling was 223 ± 11 and 45 ± 6 kJ/kg0.75 per day, respectively, whereas the energy cost of standing over lying down was 53 ± 6 kJ/kg0.75 per day. We concluded that O2P in dairy cows was slightly affected by both animal posture and activity, but remained unaffected by air temperature within 8 to 32°C. Nonlinearity of the relationship between the O2P and air temperature suggests that caution is required extrapolating O2P beyond the temperature range evaluated in our experiment.

As the pig industry develops rapidly, various problems are increasing both inside and outside pig houses. In particular, in the case of pig houses, it is difficult to solve the main problems even if automation and mechanization are applied with Information and Communications Technologies (ICT). The air recirculation technology can be applied as a technology that can solve these typical problems in the pig industry, such as growth environment, livestock disease, odor emission, energy cost, and pig productivity. The air recirculated ventilation system (ARVS) can minimize the inflow of air from the outdoors and recycle the internal thermal energy of the pig house. The ARVS consists of (1) an air scrubber module, (2) an external air mixing module, (3) a UV cleaning module, (4) a solar heat module, and (5) an air distribution module. In this study, the growth environment of piglets was predicted using a numerical model when the ARVS was applied. Since the concept of air recirculation was used, numerous equations for predicting the internal environment should be iteratively calculated. Furthermore, it was necessary to determine the optimum condition of the modules by applying various boundary conditions. Therefore, the model was designed for numerical analysis based on the balance equations of environmental factors inside the piglet room. For each module, the module coefficient and equations were considered based on the previous studies. The analysis was conducted according to the system diagram of each module, and the growth environment inside the piglet room was evaluated according to the various environmental conditions. As a result of calculating the numerical model, the ventilation rate of 40 CMM or more was advantageous to properly maintaining the gas environment. In the summer season, it was necessary to additionally use the cooling device and dehumidifier. In the winter season, when using a heat exchanger and solar module, was more advantageous for maintaining air temperature inside the piglet room.

This study determined the effects of increasing ambient temperature (T) at different relative humidity (RH) and air velocity (AV) levels on the physiological and productive responses of dairy cows. Twenty Holstein dairy cows were housed inside climate-controlled respiration chambers, in which the climate was programmed to follow a daily pattern of lower night and higher day T with a 9°C difference, excluding effects from sun radiation. Within our 8-d data collection period, T was gradually increased from 7 to 21°C during the night (12 h) and 16 to 30°C during the day (12 h), with an incremental change of 2°C per day for both nighttime and daytime T. During each research period, RH and AV were kept constant at 1 of 5 treatment levels. A diurnal pattern for RH was created, with lower levels during the day and higher levels during the night: low (RH_l: 30-50%), medium (RH_m: 45-70%), and high (RH_h: 60-90%). The effects of AV were studied during the day at 3 levels: no fan (AV_l: 0.1 m/s), fan at medium speed (AV_m: 1.0 m/s), and fan at high speed (AV_h: 1.5 m/s). Effects of short and long exposure time to increasing T were evaluated by collecting data 2 times a day: in the morning [short: 1 h (or less) - exposure time] and afternoon (long: 8 h - exposure time). The animals had free access to feed and water and both were ad libitum. Respiration rate (RR), rectal temperature (RT), skin temperature (ST), dry matter intake, water intake, milk yield, and composition were measured. The inflection point temperatures (IPt) at which a certain variable started to change were determined for the different RH and AV levels and different exposure times. Results showed that IPt under long exposure time for RR (first indicator) varied between 18.9 and 25.5°C but was between 20.1 and 25.9°C for RT (a delayed indicator). The IPt for both RR and RT decreased with higher RH levels, whereas IPt increased with higher AV for RR but gave a minor change for RT. The ST was positively correlated with ambient T and ST was not affected by RH but significantly affected by AV. For RR, all IPt was lower under long exposure time than under short exposure time. The combination of higher RH levels and low AV level negatively affected dry matter intake. Water intake increased under all treatments except RH_l-AV_l. Treatment RH_h-AV_l negatively affected milk protein and fat yield, whereas treatments RH_m-AV_m and RH_m-AV_h reduced milk fat yield. We concluded that RH and AV significantly affected the responses of RR, RT, ST, and productive performance of high-producing Holstein cows. These responses already occurred at moderate ambient T of 19 to 26°C.

This study aimed to investigate the impact of decreased crude protein (CP) levels (by 2% units) or acidifying diets (by adding 10 g benzoic acid/kg diet in combination with replacing a part of CaCO3 by about 10 g Ca-formate/kg diet) on urine, feces and manure composition and ammonia emissions from growing and finishing pig houses. Yorkshire x F1(Landrace x Yorkshire) pigs (n = 576) with an initial body weight of 24.9 ± 3.4 kg were randomly allocated to four treatments of (i) a control diet with normal protein content and no acidifying components added; (ii) a diet with 2% units CP reduction; (iii) a diet with an acidifying effect on the manure; (iv) or a diet consisting of a combination of diet (ii) and (iii). Pigs were housed in four mechanically ventilated and temperature-controlled rooms. Results showed that decreasing the dietary CP levels by 2% units reduced the ammonia emission from the floor by 46% (p = 0.06) and from the pig house by 31% (p = 0.08). Decreased CP diets reduced the total N in feces and in manure and NH4-N in the manure, as well as the ammonia concentration at 1 cm and 10 cm above the manure surface (p < 0.05). However, acidifying diets failed to reduce ammonia emissions from the floor and the pig house (p > 0.05). Reducing dietary crude protein is, therefore, a solution to reducing ammonia emissions from pig houses.

The focus of this study was to identify the effects of increasing ambient temperature (T) at different relative humidity (RH) and air velocity (AV) levels on heat loss from the skin surface and through respiration of dairy cows. Twenty Holstein dairy cows with an average parity of 2.0 ± 0.7 and body weight of 687 ± 46 kg participated in the study. Two climate-controlled respiration chambers were used. The experimental indoor climate was programmed to follow a diurnal pattern with ambient T at night being 9°C lower than during the day. Night ambient T was gradually increased from 7 to 21°C and day ambient T was increased from 16 to 30°C within an 8-d period, both with an incremental change of 2°C per day. A diurnal pattern for RH was created as well, with low values during the day and high values during the night (low: RH_l = 30-50%; medium: RH_m = 45-70%; and high: RH_h = 60-90%). The effects of AV were studied during daytime at 3 levels (no fan: AV_l = 0.1 m/s; fan at medium speed: AV_m = 1.0 m/s; and fan at high speed: AV_h = 1.5 m/s). The AV_m and AV_h were combined only with RH_m. In total, there were 5 treatments with 4 replicates (cows) for each. Effects of short and long exposure time to warm condition were evaluated by collecting data 2 times a day, in the morning (short: 1-h exposure time) and afternoon (long: 8-h exposure time). The cows were allowed to adapt to the experimental conditions during 3 d before the main 8-d experimental period. The cows had free access to feed and water. Sensible heat loss (SHL) and latent heat loss (LHL) from the skin surface were measured using a ventilated skin box placed on the belly of the cow. These heat losses from respiration were measured with a face mask covering the cow's nose and mouth. The results showed that skin SHL decreased with increasing ambient T and the decreasing rate was not affected by RH or AV. The average skin SHL, however, was higher under medium and high AV levels, whereas it was similar under different RH levels. The skin LHL increased with increasing ambient T. There was no effect of RH on the increasing rate of LHL with ambient T. A larger increasing rate of skin LHL with ambient T was observed at high AV level compared with the other levels. Both RH and AV had no significant effects on respiration SHL or LHL. The cows lost more skin sensible heat and total respiration heat under long exposure than short exposure. When ambient T was below 20°C the total LHL (skin + respiration) represented approx. 50% of total heat loss, whereas above 28°C the LHL accounted for more than 70% of the total heat loss. Respiration heat loss increased by 34 and 24% under short and long exposures when ambient T rose from 16 to 32°C.

This study developed a three-node mechanistic model to simulate processes of Holstein dairy cows physiological regulation and heat dissipation under various environmental conditions based on bio-physical laws. This model calculated the heat flow through three main nodes at the body core, skin and coat of a cow. Heat production by the animal and heat flow between the animal and the environment, including convection, long-wave radiation, skin evaporation and respiration, were calculated. Sub models of physiological regulation, including tissue resistance, respiration and sweating rate, were developed using the training dataset from an experiment conducted recently in climate-controlled respiration chambers, providing an improved modelling of the thermo-physiological process of dairy cows. The model requires information of climate and animal characteristics as inputs, and outputs body core, skin and coat temperatures. This model was evaluated through the testing experimental dataset. The root mean squared errors of prediction for body core and skin temperatures were 0.3 and 1.2 degrees C, respectively. This model was able to calculate dynamic changes in body core heat storage and the body and skin temperature variations. A simulation study was conducted on a dairy cow with 600 kg of body weight and 30 kg of daily milk yield with increasing ambient temperature at different relative humidity and air velocity levels. The predicted effects of environmental factors on the thermal responses were generally in line with the experimental results. The model is reliable to predict the thermal status of dairy cows and to predict the benefits of cooling methods and their limitations.(c) 2022 The Authors. Published by Elsevier Ltd on behalf of IAgrE. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).