Sirvi Autor "Andrade, R.R." järgi

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Alternative form to obtain the black globe temperature from environmental variables
(2019) Zanetoni, H.H.R.; Tinôco, I.F.F.; Barbari, M.; Conti, L.; Rossi, G.; Baêta, F.C.; Vilela, M.O.; Teles Junior, C.G.S.; Andrade, R.R.
Reaching thermal comfort conditions of animals is essential to improve well-being and to obtain good productive performance. For that reason, farmers require tools to monitor the microclimatic situation inside the barn. Black Globe-Humidity Index (BGHI) acts as a producer management tool, assisting in the management of the thermal environment and in decision making how protect animals from heat stress. The objective of this work was to develop a mathematical model to estimate the black globe temperature starting from air temperature, relative humidity and air velocity. To reach this goal, data of air temperature and humidity were collected, with the aid of recording sensors. The black globe temperature was measured with a black copper globe thermometer and the air velocity was monitored with a hot wire anemometer. Data were analysed using a regression model to predict the black globe temperature as a function of the other variables monitored. The model was evaluated, based on the significance of the regression and the regression parameters, and the coefficient of determination (R²). The model proved to be adequate for the estimation of the black globe temperature with R2 = 0.9166 and the regression and its parameters being significant (p < 0.05). The percentage error of the model was low (approximately 2.2%). In conclusion, a high relation between the data estimated by the model with the data obtained by the standard black globe thermometer was demonstrated.
Analysis of environmental conditions and management in a compost-bedded pack barn with tunnel ventilation
(2021) Yameogo, B.; Andrade, R.R.; Teles Júnior, C.G.S.; Laud, G.S.; Becciolini, V.; Leso, L.; Rossi, G.; Barbari, M.
The housing system based on compost-bedded pack for dairy cows is spreading rapidly in Brazil. Completely open buildings without curtains and simple roofs are usually provided. However, in the last years some new completely closed barns have been realized. This study aims to analyse one of these closed barns, located in the State of Minas Gerais. The two main sides of the facility are provided with polyethylene curtains of blue colour and five deflectors. The barn is equipped with an evaporative adiabatic cooling system, associated with the tunnel-style ventilation, realized with exhaust fans, continuously operating 24 hours a day. 85 lactating Holstein cows were housed in the barn during the trials carried out in the winter season 2019. Microclimatic data were collected continuously. Air speed, illuminance and bedding temperature were measured during the farm visits. Pack moisture was calculated. The results state the importance of bedding management and climatic conditions inside the barn. It emerges that the cows housed in this kind of closed barn, with forced ventilation, are in good thermal conditions, which are fairly constant. The average illumination of the barn can be considered acceptable (55.06 lx), even if some areas of the barn present values below the minimum ones reported in literature. The bedding temperature varies between a maximum of 36.33 °C and a minimum of 25.44 °C with an average of 31.26 °C. The values of bedding moisture are between a maximum of 64.36% and a minimum of 60.81% with an average of 62.48%.
Analysis of environmental conditions in two different Compost Bedded Pack Barn systems for dairy cattle
(Estonian University of Life Sciences, 2023) Andrade, R.R.; Tinôco, I.F.F.; Damasceno, F.A.; Valente, D.A.; Oliveira, C.E.A.; Oliveira, V.C.; Rossi, G.; Barbari, M.
The objective of this study was to analyse and compare the thermal environment of dairy cattle facilities in an open compost bedded pack barn (CBP) with natural ventilation and closed CBP (without thermal insulation) and climate control system. The research was conducted in a property located in Zona da Mata, Minas Gerais, Brazil. During the summer and for different periods of the day, the following average environmental variables observed inside the facilities were measured: dry bulb temperature, relative humidity and Temperature and Humidity Index (THI). The results were submitted to an analysis of variance to determine the significance of the variables in the different treatments. It was found that the closed and climate control system CBP promoted greater control of the facility's internal microclimate, registering smaller thermal amplitudes and a greater reduction in the animals' exposure time to stressful thermal conditions, compared to the CBP with natural ventilation. However, during summer afternoons, comfort indices indicated moderate stress. It is concluded that the closed CBP, regarding the analysed variables, indicated potential use, provided that a careful study of the climate of the region is carried out before implementation, the factors related to the ambient conditioning and better insulation of the construction are adjusted. The climatic variables inside the open CBP indicated a high stress condition for the animals, suggesting the placement of positive pressure fans and sprinklers properly distributed in the feed alley, to guarantee benefits to the entire area of the animal housing.
Behavioural patterns of cows housed in two different typologies of compost-bedded pack barns
(2021) Yameogo, B.; Andrade, R.R.; Teles Júnior, C.G.S.; Laud, G.S.; Becciolini, V.; Leso, L.; Rossi, G.; Barbari, M.
The compost-bedded pack barn (CBP) is an innovative housing technique which has the improvement of animal welfare as main objective. A comparative study of the behaviour of Holstein-Friesian dairy cows housed in two different compost-bedded pack barns located in the State of Minas Gerais (Brazil) was carried out during the winter season. One barn (CBP A) is closed and applies a wind tunnel ventilation (negative pressure). A second barn (CBP B) is open with natural ventilation, without curtains on the sides, and has fans placed in the resting area. Infrared video cameras were installed in the two barns to allow continuous and simultaneous monitoring of cows’ behaviour. Air temperature and relative humidity inside the barns were monitored continuously and Temperature-Humidity Index was consequently calculated. The results show that the cows housed in the closed barn, with forced ventilation (CBP A), were in good thermal conditions, which were fairly constant, while in the open barn (CBP B) the internal microclimatic conditions were more subject to outside climatic conditions. A close relationship was found between the trend of air temperature and relative humidity inside the facilities and the behaviour of the cows. The number of cows at rest, in CBP B, decreased as the THI value rose. In CBP A, the behaviour of the cows in relation to THI was much more constant.
Comparative analysis of performance by cows confined in different typologies of compost barns
(2020) Valente, D.A.; Souza, C.F.; Andrade, R.R.; Tinôco, I.F.F.; Sousa, F.C.; Rossi, G.
The compost barn system was designed to be a sustainable alternative housing system for dairy cows. In order to help producers in the region to choose the best type of facility from the point of view of the milk production of the animals, this study compared the productivity of cows confined in an open composting barn with natural ventilation and in a closed composting barn with negative pressure ventilation and evaporative cooling panels. The temperature and relative humidity of the air were monitored, as well as the milk production of the animals housed in the facilities, and THI (Temperature and Humidity Index) were calculated. During the trials, the maximum daily temperatures of the air reached values around 27 °C and the THI remained within the normal range of up to 70. The average productivity remained in the general pattern described in the literature from 23 to 44 kg of milk cow1 day-1 , with lower rates obtained in the closed house. As the variation of the index used to describe the internal environment was not significant, it can be inferred that climatic elements as temperature and air humidity, under the conditions analyzed were not the main factors influencing the productivity rates of dairy cattle. In conclusion, under the analysed conditions the use of a closed barn with negative pressure ventilation is hardly justified as a plant that favoured the productivity of the confined cows.
Comparison of airflow homogeneity in Compost Dairy Barns with different ventilation systems using the CFD model
(2020) Fagundes, B.; Damasceno, F.A.; Andrade, R.R.; Saraz, J.A.O.; Barbari, M.; Vega, F.A.O.; Nascimento, J.A.C.
In the pursuit of high milk productivity, producers are using confinement systems in order to improve performance and animal welfare. Among the housing systems, the Compost bedded-pack barns (CBP) stand out. In these barns a bedding area is provided inside, where cows move freely. Generally this area is covered with carbon source material (such as sawdust or fine dry wood shavings) which together with manure, thanks a regular mechanically stirring, ensures the aerobic composting process. The ventilation in these facilities has the function of dehumidifying the air, improving the air quality, drying the bedding, improving the thermal comfort conditions of the confined animals. This work aimed at validating a computational model using Computational Fluid Dynamics (CFD) to determine the best homogeneity of airflows generated by different forced ventilation systems used in CBP barns. Two CBP barns were compared with different ventilation systems: high volume low speed (HVLS) and low volume high-speed (LVHS) fans. The results showed that the proposed model was satisfactory to predict the flows generated by both types of fans. It was concluded that the use of HVLS fans produced a more homogeneous airflow when compared to LVHS fans. The use of mechanical ventilation in tropical conditions is necessary for the proper functioning of the system. In this study, the systems used promoted the increase in air speed to levels close to adequate.
Computational fluids dynamics (CFD) in the spatial distribution of air velocity in prototype designed for animal experimentation in controlled environments
(2019) Vilela, M.O.; Gates, R.S.; Martins, M.A.; Barbari, M.; Conti, L.; Rossi, G.; Zolnier, S.; Teles Junior, C.G.S.; Zanetoni, H.H.R.; Andrade, R.R.; Tinôco, I.F.F.
Maintaining a comfortable and productive thermal environment is one of the major challenges of poultry farming in tropical and hot climates. The thermal environment encompasses a number of factors that interact with each other and reflect the actual thermal sensation of the animals. These factors characterize the microclimate inside the facilities and influence the behaviour, performance and well-being of the birds. Thus, the objective of this study is to propose and validate a computational model of fluid dynamics to evaluate the spatial distribution of air velocity and the performance of a system designed to control air velocity variation for use in experiments with birds in controlled environment. The performance of the experimental ventilation prototype was evaluated based on air velocity distribution profiles in cages. Each prototype consisted of two fans coupled to a PVC pipe 25 cm in diameter, one at each end of the pipe, with airflow directed along the entire feeder installed in front of the cages. The contour conditions considered for the simulation of airflow inside the cage were air temperature of 35 °C at the entrance and exit of the cage; air velocity equal to 2.3 m s -1 at the entrance of the cage; pressure of 0 Pa. The model proposed in this study was representative when compared to the experimental measurements, and it can be used in the study of air flow behaviour and distribution for the improvement of the prototype design for later studies.
Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia
(2019) Cândido, M.G.L.; Tinôco, I.F.F.; Barbari, M.; Freitas, L.C.S.R.; Dos Santos, T.C.; Andrade, R.R.; Gates, R.S.; Conti, L.; Rossi, G.
Poultry production in subtropical and tropical regions faces many problems, one of which is the high air temperature causing thermal stress, particularly dangerous in high-producing birds. Thus, the negative effects caused by heat stress (HS) must be managed. The objective of this study was to evaluate the effects of four different levels of HS in viscera and tibia of pullets. A total of 648 chicks (Lohmann LSL Lite) were used in this study in two different phases. The pre-experimental phase (PEP) was from day 1 through 6 weeks of age. The birds were reared with three different environmental temperatures: thermal comfort, hot and cold. The experimental phase (EP) was conducted from the 7th to the 17th week. Pullets from each thermal environment of the PEP were submitted to: 20 °C, 25 °C, 30 °C, 35 °C. At the end of the 17th week of age 120 pullets were euthanatized and the organs, heart, liver, spleen and gizzard were weighed, as also their tibias. Effects of PEP, and its interaction with EP, were not significant (P < 0.05) for viscera and tibia weight. However, a significant increase (P < 0.05) in heart weight with the decrease of the environmental temperature was observed, being the pullets subject to 20ºC and 25 °C with the heaviest weights. For the liver, pullets subject to the 35 °C had the lowest weight and were different (P < 0.05) from the other three treatments. For gizzard, the difference (P < 0.05) was between the treatments 20ºC and 35 °C. These results indicate that brooding temperatures tested during the first 6 weeks of life did not affect the viscera and bone weight during the growing phase.
Effect of thermal environment on body temperature of early-stage laying hens
(2018) Andrade, R.R.; Tinôco, I.F.F.; Souza, C.F.; Oliveira, K.P.; Barbari, M.; Cruz, V.M.F.; Baptista, F.J.F.; Vilela, M.O.; Conti, L.; Rossi, G.
The thermal comfort condition of early - stage laying hens can be verified by means of physiological variations. The mean surface temperature and cloacal temperature are important parameters to d emonstrate the effect of the thermal environment on the birds. The objective of the present study was to correlate homeostasis and stress with physiological responses (mean surface temperature and cloacal temperature) of lightweight laying hens of the Lohm ann LSL Lite line aged from one to forty - two days when submitted to different thermal environments. A total of 864 birds with the same age, origin and uniform body weight were randomly distributed in four climatic chambers. The characterization of the dif ferent environments was as follows: thermal comfort temperature (33.0 – 19.0 °C ), two cold stress levels (28.0 – 17.0 °C and 25.0 – 17.0 °C ) and one level of heat stress (38.0 °C – 22.0 °C ). The experiment was performed in a completely randomized design in the s ubdivided plots scheme, with four treatments in the plots and the evaluations (days) in the subplots. The means were compared using the Tukey test, adopting the 5% probability level. The birds maintained the physiological responses, based on cloacal and su rface temperatures, within the normal range for all evaluated treatments during the period between 01 and 42 days of life. The surface temperature of the birds varied as a function of the air temperature of each breeding environment, with lower surface temperatures for mild cold and moderate cold treatments.
Energetic analysis in compost dairy barn: a case study in southeastern Brazil
(Estonian University of Life Sciences, 2023) Cruz, E.F.L.; Hernández, R.O.; Damasceno, F.A.; Tinôco, I.F.F.; Andrade, R.R.; do Nascimento, J.A.C.; Rossi, G.; Becciolini, V.; Barbari, M.
Energy efficiency aims to optimize the energy consumption of the processes, activities, and machinery of the farm, ensuring the comfort, handling, and safety of the animals. The purpose of the study was to identify the energy consumption demanded by the activities performed at the Compost Dairy Barn facility, located in Itaguara, Minas Gerais, Brazil and to propose energysaving alternatives, applying the Energy Audit Methodology described by the Institute for Energy Diversification and Saving (IDAE in Spanish) from Spain. The energy assessment at the facility allowed us to recognize unnecessary energy expenses in machinery uses, variations in milk production in relation to environmental conditions, waste disposal, and to propose improvement alternatives to reduce energy consumption expenses. Waste production data of 1577.7 kg per year was obtained, which corresponds to the bedding and feeding areas, and 175 kg of waste for the feeding area. Data on the temperature and humidity of the bedding area were collected to determine which of the five months of research is the most demanding in terms of energy. To maintain the animal’s welfare, tracing the times of substantial use of machinery (e.g., fans, tractors) at the facility and calculating Equivalent Temperature Index (ETI) was necessary. The highest percentage consumption of energy was represented by tractors in bedding maintenance and supply, by around 95.03%. The energy analysis of the farm showed a reduction in energy consumption of 45.03%, compared to the initial consumption percentages of the overall livestock activity.
Estimate of manure present in compost dairy barn systems for sizing of manure storage
(2020) Damasceno, F.A.; Monge, J.L.; Nascimento, J.A.C.; Andrade, R.R.; Barbari, M.; Saraz, J.A.O.; Ferraz, G.A.S.
Milk production is increasingly modernized as a result of the growing demand for food around the world. Improvements in livestock facilities are observed, with a large increase in the use of feedlot systems such as the Compost Dairy Barn. Increasing milk production in confinement systems has also raised concerns such as the management of wastes (water, faeces and urine) from the system, which has become one of the most important issues in the intensive dairy farms. The aim of this work was to estimate the amount of manure present in compost dairy barn systems in order to size the manure storage. The study was conducted at four compost dairy barns in southern Minas Gerais, Brazil. These compost barns had different bedding materials and dimensions. In each farm, data on milk yield and quality (daily production, fat and protein content), animal weight and amount of feed ingested by the animals were collected. Total-day manure delivered by the cows in the feeding alley and milking parlour was piled up together and weighed. Based on the results, it was observed that, in the compost dairy barns, only part of the total manure produced per day was delivered in the milking parlour (1.6 and 2.0%) and in the feed alley (27.6 to 49.3%). These results are very important for designers for the proper manure management system design of the dairy farms.
Lighting and noise levels in compost dairy barns with natural and forced ventilation
(2020) Andrade, R.R.; Tinôco, I.F.F.; Damasceno, F.A.; Barbari, M.; Valente, D.A.; Vilela, M.O.; Souza, C.F.; Conti, L.; Rossi, G.
The housing system, called compost barn, is attracting the interest of several farmers. It allows dairy cows to remain in free movement inside a shed without any containment partitions like those used in freestall barns. In Brazil the compost barns with open sides are very common, but recently some closed barns with climatic control systems have been implemented. The objective of this work was to evaluate and compare lighting and noise levels in an open compost barn with natural ventilation and in a closed compost barn with a climate control system. The latter one is based on tunnel ventilation: inlet of air trough evaporative cellulose panels and exit through fans placed on the opposite wall. Through analysis of the collected data it was observed that the sound pressure recorded inside both analysed buildings did not exceed the ranges of noise discomfort recommended for the rearing of animals. However, the sound pressure amplitude inside the barn with climate control system was greater than in the open barn. The light intensity was significantly lower in the closed barn when compared to the open barn (84.96 and 1,413.58 lx, respectively). The artificial lighting system distributed throughout the closed barn was not sufficient to maintain brightness within the recommended range for lactating cows. In addition, it was found that in the closed building with forced ventilation, the highest brightness values are located near the exhaust fans.
Milk Production Response of Dairy Cows to Climatic Variables in a Compost-Bedded Pack Barn: A Case Study in the Brazilian Savanna (Cerrado)
(Estonian University of Life Sciences, 2026) Rosa, D.R.; Ribeiro, M.D.; Ferreira, N.C.R.; Arnhold, E.; Santos, N.I.P.; Barbari, M.; Bambi, G.; Andrade, R.R.
High temperatures, humidity, and heatwaves negatively impact dairy cattle welfare, reducing milk yield. This study evaluated the seasonal associations and trends between THI, air temperature, humidity, and milk yield in multiparous Holstein cows housed in a compost-bedded pack barn system from 2021 to 2023 was obtained from farm records. Air temperature (tair), relative humidity (RH), and the Temperature-Humidity Index (THI) were calculated. Data were analyzed quarterly using the Scott–Knott test, Pearson’s correlation, and simple linear regression. AMP was significantly higher (P < 0.01) from June to November (winter/spring). Correlation between AMP and THI was low (r = -0.02, P = 0.89). However, tair showed a moderate positive correlation (r = 0.36, P < 0.05) with the regression estimating an increase of 0.32 kg per degree Celsius. Conversely, RH was negatively correlated (r = -0.40; P < 0.05), with the model estimating a 0.05 kg decrease in milk per unit increase of RH. Although tair and RH significantly affect production, they interact with wind speed and solar radiation, influencing thermal load, contributing to a scenario of greater thermal stress. Furthermore, genetics, nutrition, and management are crucial mitigating factors. Properly managed, the CBP system provides a thermally adequate environment for dairy cows. However, the evaluated CBP system presented thresholds higher than those recommended in the literature.
Physiological and behavioural parameters of broiler chicks grown under different heating systems
(Estonian University of Life Sciences, 2023) Ferraz, P.F.P.; Andrade, E.T.; Vilas Boas, R.B.; Yanagi Junior, T.; Andrade, R.R.; Becciolini, V.; Barbari, M.
This study aimed to compare the internal environment, physiological variables, and behavioural responses of chicks under two different heating systems. The experiment was performed in two commercial broiler houses located in Brazil, where 28,000 male Cobb chicks were housed during the first three weeks of life. One of the broiler houses was heated by an industrial indirect-fired biomass furnace (S1). In addition, another heating system consisting of two furnaces for indirect heating of the air using biomass (wood) as fuel, built by hand with bricks, mud, and dung on an iron structure (S2), was tested. Measurements of the dry bulb temperature (tdb), dew point temperature (tdp), and relative air humidity (RH) were performed. Subsequently, the temperature-humidity index (THI) was calculated. In addition, the physiological variables of the respiratory rate (RR) and cloacal temperature (tcloacal) were measured three times a day (8:00 am, 2:00 pm, and 6:00 pm) in four chicks. The behaviours were grouped by dendrograms, in which the similarity of these data was qualified. During the second and third weeks of life, the THI values were below the recommended range. The RR and tcloacal data were below the recommended comfort values, which may be an indicator that the chicks were subjected to cold conditions. Regarding their behaviour, the chicks exhibited calm, feeding, and sleepy behaviours most of the time. Problems in the heating system inside the broiler house could be observed, possibly affecting the chicks’ thermal comfort and welfare, which consequently can result in productive and economic losses.
Productive performance of broilers at the final stage of breeding submitted to different levels of metabolizable energy in different thermal environments
(2018) Oliveira, K.P.; Ferreira, C.F.S.; Tinoco, I.F.F.; Andrade, R.R.; Barbari, M.; Cruz, V.M.F.; Baptista, F.J.F.; Vieira, M.F.A.; Conti, L.; Rossi, G.
The Brazilian poultry industry is an activity in constant development due to the high indices of productive efficiency. The accelerated evolution of poultry production has allowed to obtain early and very efficient broilers able to convert different foods into animal protein. However, due to this intensive breeding system, a series of metabolic and management problems appeared, with emphasis on thermal stress. The objective of this work was to evaluate the physiological responses of broiler chickens in the final stage of breeding (21 to 42 days of life), submitted to two thermal conditions, one representative of the thermoneutrality situation (T1) and one giving a situation of cyclic stress by heat (T2). For each experimental thermal condition, the birds were submitted to different levels of metabolizable energy of 3,050, 3,125, 3,200, 3,275 kcal kg - 1 . At 28, 35 and 42 days, the birds and the feed leftovers were weighed to measure the performance variables: CR (feed intake), GP (weight gain) and CA (feed conversion), viability of the rearing (Vb), productive efficiency index (PEI). As conclusions, the GP was 13.6% higher for the birds maintained at the thermoneutrality situation T1. Th e PEI was 32.5% higher for the birds maintained in T1 condition, when compared to those kept in T2. However, both in thermoneutral and in heat stress conditions, the increase in the level of metabolizable energy in the diet did not influence the performanc e and the productive efficiency index of broiler chickens aged between 21 and 42 days of age.
Temporal analysis of pasture vegetation cover in central-western Brazil using remote sensing
(Estonian University of Life Sciences, 2025) Moreira, A.N.H.; Ciappina, A.H.; Andrade, R.R.; Casaroli, D.; Rossi, G.; Conti, L.; Bambi, G.
Brazil is the world's leading exporter of beef, consolidating beef cattle farming as an important branch of national livestock farming. The expansion of livestock farming and agriculture in recent decades has resulted in a notable increase in pasture areas in Brazil. However, the country faces the growing challenge of pasture degradation, a problem that threatens sustainability and food production. On the other hand, livestock farming in Brazil's Central-West region, the country's largest cattle-producing area, particularly in the state of Goiás, can cause environmental damage when sustainable practices are disregarded. Thus, the objective of this article was to evaluate pasture degradation, at different levels, in the Ribeirão Serra Negra Watershed, in the municipality of Piracanjuba, Goiás, Brazil. Using images from the Sentinel-2A orbital sensor, the NDVI (Normalized Difference Vegetation Index) vegetation index and the vegetation cover classes of pastures were obtained between 2017 and 2021. During this period, the results showed that more than 98% of the areas had some level of degradation, with an average coverage of 6,586.1 ha. There was an upward evolution in the levels of vegetation cover between 2017 and 2019, with the best pasture conditions predominating in 2019. These assessments help identify areas that require greater attention and often necessitate conservation practices and management plans. In this context, monitoring degraded areas is a practice that facilitates the improvement of existing pastures, promotes the rational management of inputs, conserves natural resources, and aligns with development programs focused on sustainability.
Variable velocity system for evaluating effects of air velocity on Japanese quail
(2020) Vilela, M.O.; Gates, R.S.; Zolnier, S.; Barbari, M.; Teles Junior, C.G.S.; Andrade, R.R.; Rocha, K.S.O.; Tinôco, I.F.F.; Souza, C.F.; Conti, L.; Rossi, G.
This study documents the design and performance of a system to apply different magnitudes of air velocity to Japanese quail, to evaluate the combined effects of velocity, temperature and humidity on bird behaviour, performance and welfare. The system was developed to simulate observed field conditions ocurring in regions with high winds where quail are raised in curtain-sided housing. System performance consisted of characterizing air velocity distribution in cages downstream of the air velocity which was directed at the front of the cages. The system consisted of two fans attached to a 25 cm PVC tube, one at each end, with the outlet airflow directed through a continuous slot over the cage front at the feeder. The design and performance of this experimental system was evaluated, with six such systems were built and utilized in research trials. To assess system performance, air velocity was measured at 275 points per cage uniformly arranged along the three dimensions (length, width and height) in eight cages with zero, 1, 2 or 3 m s-1 nominal velocity setpoints. Spatial distribution of velocity was analysed by mapping and from descriptive statistics, with attention to the zone closest to the feeder where birds must go to eat. There was no significant difference (P > 0.05) found in mean paired difference of air speed data measured for pairs of front portion cages with similar velocities. A significant positive correlation was found (P < 0.001) between the measured air velocity at paired points in the cages subjected to the same velocity treatment. A comparison of measured mean air velocity to the nominal setpoint values used for experiments indicated that careful attention to outlet adjustment is important, especially at higher nominal velocity setpoint as 3 (± 0.10) m s-1 which was difficult to achieve with the system. An example of the use of the deployment of the variable velocity system in controlled environment chambers with Japanese quail is provided.

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