RESUMO: Objetivou-se com o presente trabalho avaliar o efeito do pré-resfriamento da água usada no molhamento de placas porosas de sistemas de resfriamento evaporativo (SRE) sobre o ambiente térmico. O experimento foi realizado em dois modelos físicos construídos em escala reduzida e distorcida que simularam instalações agrícolas fechadas, equipadas com SRE composto por painéis porosos de celulose. Em um modelo físico, o molhamento das placas foi realizado por meio de água resfriada (SRAR) e o outro por meio de água natural à temperatura ambiente (SRAN). Mensurou-se a temperatura de bulbo seco do ar (tbs), temperatura de globo negro (tgn) e umidade relativa do ar (UR) no interior dos modelos físicos e no ambiente externo em intervalos de 10s. Posteriormente, foram calculados índices ambientais, a efetividade de resfriamento do SRAN e fator de desempenho do SRAR. O pré-resfriamento da água usada no molhamento de placas porosas de SRE propiciou maior redução nas variáveis térmicas e índices de conforto em relação ao molhamento com água à temperatura ambiente, sendo proposta uma equação empírica para a estimativa do fator de desempenho de resfriamento aplicada ao SRAR em função da temperatura da água, da tbs e da temperatura de bulbo úmido do ar.

ABSTRACT: This study assessed the ways the thermal environment is influenced by pre-cooling the water employed in wetting the porous plates present in the evaporative cooling systems (ECS). The experiment was performed using two physical models constructed on a distorted and reduced scale, which simulated closed agricultural facilities equipped with ECS made up of porous cellulose panels. In one physical model, the plates were made wet using chilled water (ECScw), while in the other they were moistened using natural water, at environment temperature (ECSnw). Both inside the physical models and outside, in the external environment, the air dry-bulb temperature (tdb), black globe temperature (tbg) and air relative humidity (RH) were measured, at 10 sec intervals. Later, the environmental indices, ECSnw cooling effectiveness and ECScw performance factor were assessed. When the porous ECS plates were thoroughly wet using pre-cooled water, lowering of the thermal variables and comfort indices was seen to be greater than when wetting the plates was done using water at room temperature. An empirical equation was proposed to determine the cooling performance factor applied to the ECScw related to water temperature, tdb and air wet-bulb temperature.

ABSTRACT The thermal and luminous conditions in aviaries affect the production and quality of eggs. Thus, the aim of the present study was to evaluate the thermal and luminous environment of commercial laying hen aviaries equipped with compact fluorescent (CF) and light-emitting diode (LED) lamps and their influence on egg production and quality. The study was carried out in two commercial laying hen facilities with similar construction features and management. The first facility was illuminated with CF lamps and the second with LED lamps. The thermal environment was assessed via air temperature, air relative humidity, and enthalpy. The evaluated lamps provided a similar thermal environment in both facilities. The aviary equipped with LED lamps showed higher illuminance than the one equipped with a CF lamp. Production performance was evaluated through feed intake (FI), feed conversion (FC), mortality (M), and laying percentage (LP). Specific gravity (SG) was used to evaluate eggshell quality. The variables related to production performance and eggshell quality of laying hens raised in aviaries equipped with LED lamps were statistically equal (F-test, p > 0.05) to those raised in aviaries equipped with CF lamps. These results indicate that the replacement of CF lamps with LED lamps does not adversely affect the yield and quality of eggs.

ABSTRACT The objective of this study was to characterize the thermal environment and evaluate the behavior of finishing pigs housed in deep bedding and conventional systems. The work was carried out in the Department of Animal Science of the Federal Institute of Education, Science and Technology of Southeast Minas Gerais, Rio Pomba campus. Three pens were used in an installation for breeding pigs in their finishing phase. Two pens contained deep bedding, with wood shavings and rice husks. The remaining pen was a conventional system. The behavior of the piglets was observed from 8 a.m. to 5:30 p.m., noting the behaviors with the use of an ethogram, while data relating to the thermal environment in the stalls were automatically collected using data loggers. Thermal environment data for all systems presented thermal stress conditions. Regarding behavioral variables, animals in conventional systems had a higher frequency of visits to feeders, while animals in the deep bedding system were more active and visited the drinking fountains more frequently. Despite the higher level of activity of the animals in the deep bedding system, it is not possible to confirm that the deep bedding provides a better degree of well-being for the animals under thermal stress conditions.

ABSTRACT Although dry bulb temperature (T) is the environmental variable most commonly used to classify thermal comfort in pigs, environmental assessment ratios provide more accurate information. The objective of this study was to correlate the sound pressure levels (SPL) produced by piglet vocalization with the thermal environment observed during the nursery phase, and subsequently establish thermoneutrality ranges. The experiment was conducted on a pig farm where T, relative humidity (RH), and SPL data were recorded between 9 am-5 pm for 42 days. The association between SPL and T in nursery phase piglets was verified; for thermal comfort to be possible, SPLs were 56.3 to 60.3 dB. The SPLs were subsequently used in predictor equations of ratios, and thermal comfort ranges were 74.4-78.3 for temperature and humidity ratio (THI), and 71.6-75.8 for globe temperature and humidity ratio (BGHI). Although the SPL proved to be a convenient indicator of thermal comfort for the evaluation of pigs, further studies developed in different phases of the production system are required.

ABSTRACT Due to a number of factors involving the thermal environment of a broiler cutting installation and its interaction with the physiological and productive responses of birds, artificial intelligence has been shown to be an interesting methodology to assist in the decision-making process. For this reason, the main aim of this work was to develop an artificial neural network (ANN) to predict feed conversion (FC), water consumption (Cwater), and cloacal temperature (tclo) of broilers submitted to different air dry-bulb temperatures (24, 27, 30, and 33°C) and durations (1, 2, 3, and 4 days) of thermal stress in the second week of the production cycle. Relative humidity and wind speed were fixed at 60% and 0.2 ms−1, respectively. The experimental data were used for the development of an ANN with supervised training using the Levenberg-Marquardt backpropagation algorithm. The ANN consisted of three input layers one hidden, and three output with sigmoidal tangent transfer functions with values between −1 and 1. The developed ANN has adequate predictive capacity, with coefficients of determination (R2) for tclo, FC, and Cwater of 0.79, 0.87, and 0.97, respectively. In this way, the proposed ANN can be used as a support for decision-making to trigger poultry heating systems for broiler breeding.

Resumen El desempeño de pollos de engorde sometidos a estrés térmico en las primeras semanas de vida puede ser perjudicado, una vez que el sistema termorregulador del ave no está completamente desarrollado. El objetivo de este trabajo fue analizar los efectos de diferentes desafíos térmicos sobre el desempeño de pollos de engorde. Doscientos cuarenta pollos de engorde fueron sometidos a diferentes temperaturas de bulbo seco del aire deseada (tbs: 24, 27, 30 y 33°C) y a duraciones de estrés (DE: 1, 2, 3 y 4 días) en la segunda semana de vida. El consumo de ración (CR), ganancias de peso (GP) y conversión alimenticia (CA) fueron evaluadas a los 21 días de edad de las aves. A pesar de que las diferencias fueron verificadas para CR (p<0,05), ninguna diferencia fue observada para GP (p>0,05). Reducciones de CA para las tbs de 24, 27 y 33°C fueron de 14,8, 8,6, y 10,1%, respectivamente. El CA más pequeño se observó a 30°C, lo cual se caracterizó como condición de confort.

Abstract The performance of broilers submitted to thermal discomfort in the first weeks of life may be impaired, since the thermoregulatory system of the bird is not fully developed. The objective of this study was to analyze the effects of different thermal challenges on the performance of broilers. Two hundred and forty broilers were submitted to different desired dry-bulb temperatures (tdb: 24, 27, 30 and 33°C) and stress duration (SD: 1, 2, 3 and 4 days) in the second week of life. Feed intake (FI), weight gain (WG) and feed conversion (FC) were evaluated at 21 days of age. Although differences were verified for FI (p <0.05), none were observed for WG (p> 0.05). Reductions of FC for the 24, 27 and 33°C tdb were 14.8, 8.6 and 10.1%, respectively. The smallest FC was observed at 30°C, indicating comfort condition.

ABSTRACT The selection of the type of fuzzy systems pertinence curve allows a better representation of the mathematical model and a smaller simulation error. We aimed to study the effect of pertinence curves in fuzzy modeling of broiler performance, created in different production systems. For the development and testing of fuzzy models, three commercial aviaries (conventional, tunnel with negative pressure, and dark house) were evaluated over one year, totaling six lots per system. For the development of the model, the input variables were enthalpy in each rearing phase (initial: phases 1, 2, and 3; growth: phase 4; and final: phase 5) and the output variables were feed intake (FE), weight gain (GP), feed conversion (FE), and the productive efficiency index (PEI). Triangular, trapezoidal, and Gaussian pertinence curves were combined and applied to represent the input and output fuzzy sets, totaling nine fuzzy models for each output variable. The combinations of pertinence curves provided adequate responses for the prediction of AL, GP, RC, and PEI. However, the selection of the types of curves should be studied on a case-by-case basis, so that the smallest possible simulation errors are obtained.

ABSTRACT Broiler chickens are classified as homoeothermic animals and require a production environment within well-defined thermal comfort intervals. Therefore, the development of algorithms (mathematical models) to control the environment that can be embedded in microcontrollers becomes necessary. Hence, this work aimed to develop a fuzzy model for predicting the productive performance of broiler chickens as a function of the thermal environment during the various breeding phases. The Mamdani inference and defuzzification methods were used, by means of the gravity center, to develop the fuzzy model. Two hundred and forty-three rules with weighting factors of 1.0 each were elaborated. Three commercial warehouses (conventional system, wind tunnel with negative pressure and dark house) were evaluated for testing of the model. We recorded the thermal environment (dry bulb temperature - tdb and relative humidity - RH) and productivity data (feed intake - FI, weight gain - WG, feed conversion - FC and productive efficiency index - PEI) over six lots in each aviary. The resulting fuzzy model was capable of forecasting FI, WG, FC, and PEI, with standard deviations and mean percentage errors of 4.16 g and 5.05%, 146.53 g and 8.04%, 0.06 g g−1 and 4.96%, and 24.51 g and 12.29%, respectively.

ABSTRACT Broiler chickens submitted to different intensities and durations of thermal stress are subject to variation in cloacal temperature and, consequently, to a decrease in performance. Given the complexity of these interactions, artificial intelligence is a useful methodology for decision-making. Thus, this study aimed to assess and predict, by means of a fuzzy model, the cloacal temperature of broiler chickens submitted to thermal stress in the second week of life, with varying durations and intensities, in climatized wind tunnels. Mamdani's inference and defuzzification methods by means of the center of gravity were used. One hundred and twenty rules were elaborated. The developed fuzzy model was used to predict the cloacal temperature of broiler chickens on the day of thermal stress as a function of air dry-bulb temperature (°C), stress duration (days), and the number of days after thermal stress. Cloacal temperature values simulated by the fuzzy model showed standard deviations and percentage errors lower than 0.02 and 0.08%, respectively, when compared to those obtained experimentally.

ABSTRACT Broiler chickens are homoeothermic animals, i.e., animals capable of maintaining their body temperature within quite narrow limits; therefore, climate change poses a great challenge to poultry. With this in mind, this research aims to evaluate the performance of broilers submitted to different commercial production systems and exposed to different future scenarios, taking into account the climate change trends. To achieve this objective, we developed and validated a fuzzy model able to predict the performance of a broiler as a function of enthalpy along its life stages. This model was developed and validated in part I of this article based on experimental data collected for one year in three aviaries: conventional, negative pressure, and dark house systems. A Mann-Kendall nonparametric test and linear regression analysis were applied to the enthalpy values, which were calculated as a function of the ambient air temperature and relative humidity in order to study the climate change trends. Later, simulations were performed using the fuzzy model for 2025, 2050, 2075, and 2100 future scenarios. Specific improvements were observed when the heating trends coincided with the initial stages of breeding; however, in general, the productive responses of broilers in the different evaluated systems worsened with the climate change trends. Faced with the climate change trends, the responses improved in the order dark house aviary > negative pressure aviary> conventional aviary.

ABSTRACT The objective of this work was to evaluate the thermal environment inside conventional cages for laying hens, with and without the use of protective screens. This research was conducted in two conventional cages (open cage), where each cage had half of its area surrounded by high density polyethylene mesh (HDPE) with a diameter of 2.0 cm, and the other half was kept fully open. Hyline W-36 and Dekalb Brown laying hens were housed in these cages. The wind speed, dry bulb temperature (tdb), black globe temperature, humidity index (BGHI), and enthalpy (H) were analyzed. The results indicate that the use of the screen reduced the wind speed inside the cage by 0.22 m s−1. The presence of the screen affected tdb, BGHI, and H in some of the evaluated periods evaluated, making these values higher than those of the treatment without screen. However, the obtained values are within or below the thermal comfort range for laying birds. Therefore, the use of HDPE screen in the cages altered their internal environment. However, it is not enough to hinder the thermal comfort of the housed animals.

ABSTRACT This study aimed to compare fuzzy systems with different configurations to predict the surface temperature (ts) of broiler chickens subjected to different intensities and durations of thermal challenges in the second week of life. Data on the ts of broiler chickens aged 8 to 11 days were acquired by infrared thermography and subjected to combinations of four dry-bulb temperatures (tdb) (24, 27, 30, and 33 °C) and four durations of thermal challenges (DTC) (1, 2, 3, or 4 days). The input variables of the fuzzy systems were tdb and DTC, and the output variable was ts. The Mamdani inference method involving five defuzzification methods [center of gravity (centroid), bisector of the area (bisector), largest of maximum (lom), middle of maximum (mom), and smallest of maximum (som)], and Sugeno inference with two defuzzification methods [weighted average (wtaver) and weighted sum (wtsum)] were evaluated. For both inference methods, triangular and Gaussian pertinence functions were tested for input and output variables, except for Sugeno inference, which used singletons functions as output variables. While developing fuzzy systems, different configurations must be compared, and the system with smaller simulation errors should be selected.

RESUMO Uma interessante maneira de se mensurar a eficiência de sistemas produtivos é por meio da análise energética, identificando quais insumos ou operações demandam mais energia. Portanto, objetivou-se no presente trabalho avaliar a eficiência energética de um sistema de criação de frangos de corte, confinados em galpões com tipologia Darkhouse. Foram considerados os fluxos de energia referentes a um ciclo completo de produção, 56 dias, onde foram computadas as entradas e saídas de energia, na forma direta e indireta, por meio da estimação da energia presente na ração, água, máquinas e equipamentos, trabalho humano, galpões, silos, dentre outros que compõem o sistema produtivo, multiplicando-se pelos seus respectivos coeficientes energéticos. Foram encontradas a demanda total de energia pelo sistema em um ciclo de produção, a energia necessária para produção de 1 kg de frango vivo e o coeficiente de eficiência energética do mesmo. O sistema estudado apresentou um coeficiente de conversão da energia de 46%, valor próximo ao encontrado para sistemas de produção animal. Foram necessários, em média, 37,55 MJ kg-1 de frango vivo. O principal ponto estrangulador do sistema correspondeu à energia consumida na forma de ração, com 75% do total da energia direta.

ABSTRACT The objective of this study was to evaluate the sustainability of a broiler chicken production system, with confinement in Darkhouse sheds, by energetic analysis. Energy flows of a complete production cycle, 56 days, were considered, of which the energy inputs and outputs were computed in direct and indirect forms, by estimating the energy coming from the quantity of feed, water, machinery and equipment, human labor, sheds, silos, among other components of the productive system, multiplied by their respective energetic coefficients. The total energy demand of a system in a production cycle for the production of 1 kg of live chicken and its energy efficiency coefficient were determined. The studied system had energy conversion coefficient of 95%, demonstrating that the production model has high energy conversion efficiency and fits a sustainable model. On average, 37.55 MJ kg-1 of live chicken were necessary. The main limiting point of the system corresponded to the energy consumed in the form of feed, with 75% of the total direct energy.

RESUMO A entalpia é uma propriedade termodinâmica que pode ser usada na avaliação do ambiente térmico para frangos, pois considera as variáveis meteorológicas que mais influenciam no conforto térmico animal, a temperatura do bulbo seco e a umidade relativa do ar. Objetivou-se analisar e comparar a variabilidade espacial da entalpia em um aviário de frangos durante três períodos do dia (manhã, tarde e noite) por 14 dias de vida das aves, empregando técnicas geoestatísticas. O experimento foi realizado em um aviário comercial onde estavam alojados 28.000 pintinhos machos da linhagem Cobb localizado na mesorregião oeste de Minas Gerais. O sistema de aquecimento consistia em um forno industrial de metal com queima indireta de biomassa. O ar aquecido foi insuflado por motor CA, 2206 W de potência, 1725 RPM. Utilizou-se técnicas de geoestatística por meio de análises de semivariograma e confecção de mapas de isocores por meio de interpolação dos dados por krigagem. O semivariograma foi ajustado pelo método da Máxima Verossimilhança Restrita. O modelo matemático utilizado foi o esférico. Após o ajuste dos semivariogramas foi realizada a interpolação dos dados por krigagem ordinária. Os semivariogramas juntamente com os mapas de isocores permitiram identificar a não-uniformidade da distribuição espacial da entalpia ao longo do aviário durante três períodos dos 14 dias análisados. Observou-se que nos primeiros dois dias de vida durante os três períodos avaliados as aves ficaram a maior parte do tempo ao longo da maior parte do galpão sob condições de entalpia abixo do recomendado pela literatura. No 12º e 13º dias de vida durante os três períodos analisados, as aves ficaram submetidas as condições mais críticas de desconforto ao longo do dia, na maior parte do aviário. Observou-se também possíveis falhas no sistema de aquecimento, principalmente no período da noite, o que pode ser uma fonte de desconforto para as aves e consequentemente gerar perdas produtivas e econômicas.

ABSTRACT The enthalpy is a thermodynamic property that can be used to evaluate thermal environment for chickens, considering the meteorological variables that most influence the animal’s thermal comfort, the dry-bulb temperature and the relative humidity. The aim was to analyze and compare the spatial variability of enthalpy in a broiler aviary during three periods of the day (morning, afternoon and night) for 14 living days, using geostatistical techniques. The experiment was performed in a commercial broiler aviary located in the western mesoregion of Minas Gerais, Brazil, where 28,000 male Cobb chicks were housed. The heating system consisted of an industrial indirect-fired biomass furnace. The heated air was inflated by an AC motor, 2206 W of power, 1725 RPM. Geostatistical techniques were used through semivariogram analysis and isochore maps were generated through data interpolation by kriging. The semivariogram was fitted by the restricted maximum likelihood method. The used mathematical model was the spherical one. After fitting the semivariograms, the data were interpolated by ordinary kriging. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the enthalpy throughout the broiler aviary for three periods during 14 days. It was observed that in the first two days of life, during the three evaluated periods the poultry kept most of the time and in most of the poultry shed under conditions of enthalpy below the recommended level in the literature. In the12th and 13th days during the three analyzed periods were the most critical because they showed values below the comfort throughout the day, over the entire broiler aviary. Possible failures in the heating system were also observed, especially at night, which can be a discomfort source for poultry and hence generate productive and economic losses.

RESUMO Diante da importância da ambiência nas instalações para suínos, objetivou-se com o presente trabalho avaliar a qualidade do ar, nível de pressão sonora e o ambiente térmico em duas instalações de creches de suínos de tipologias diferentes. O delineamento experimental foi o de blocos casualizados com parcelas subdivididas. As médias de temperatura do ar (ºC), umidade relativa do ar (%) e o índice de temperatura do globo negro e umidade (ITGU) foram comparadas pelo teste Tukey em nível de 0,05 de probabilidade. As concentrações instantâneas de amônia (ppm), dióxido de carbono (ppm) e níveis de pressão sonora (dB(C)) foram medidas três vezes ao dia e analisados por meio de gráficos boxplot. Os resultados mostram que não houve diferença entre as duas creches com relação ao ambiente térmico, aéreo e acústico. As creches podem ser consideradas desconfortáveis, para os animais no que diz respeito às condições térmicas. As concentrações dos gases e nível de pressão sonora não ultrapassaram os limites estabelecidos pela norma vigente. Em ambas as creches, apenas às 9 horas, foi possível detectar níveis de pressão sonora que caracterizam a condição de conforto térmico do ambiente, nos demais horários a condição é de alerta e estresse.

ABSTRACT Because of the importance of the ambiance in swine facilities, this study aimed to evaluate the air quality, the sound pressure level, and the thermal environment of two distinct swine nursery styles. A completely randomized block design with a split-plot arrangement was used, in which the main plots were composed of the nurseries and the external environment; the subplots were the hours; and the replications were the collection days. Air temperature data (ºC), relative humidity (%), and black globe humidity index (BGHI) data were collected throughout the day at 10-min intervals, with means compared by Tukey’s test at 0.05 probability level. Instantaneous concentrations of ammonia (ppm), carbon dioxide (ppm), and sound pressure levels (dB(C)) were measured three times daily and analyzed on boxplot graphs. The results showed no difference between the two nurseries with respect to thermal, air, and acoustic environment. The nurseries can be considered uncomfortable for the animals with respect to thermal conditions. Concentrations of gases and sound pressure levels did not exceed the limits established by current regulations. In both nurseries only at 09h00 it was possible to detect sound pressure levels that characterize the condition of comfort thermal of the environment, at the other times, alert and stress conditions were observed.