Analysis of environmental conditions in two different Compost Bedded Pack Barn systems for dairy cattle

Received: February 1st, 2023 ; Accepted: April 27th, 2023 ; Published: May 10th, 2023 ; Correspondence: [email protected], [email protected] 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

A software to estimate heat stress impact on dairy cattle productive performance

ArticleThe aim of this study is to develop a computational tool, based on the Temperature and Humidity Index value, to characterize the thermal environment in dairy cattle barns and to evaluate the impact of thermal stress on productive performance. The software for the thermal environment prediction, and determination of the influence of heat stress on dairy cow productivity (Ambi + Leite) was developed using the C# programming language in the Microsoft Visual C# 2010 Express Integrated Development Environment. The following scenario was considered for the program test: air temperature 32°C, relative air humidity 70% and milk production potential in thermoneutrality condition 20 kg cow-1 day-1 . The prediction of the thermal environment based on the simulated situations indicates that the animals are submitted to a moderate heat stress condition with THI equal to 82.81. In this condition a decrease of approximately 26% in milk production and a reduction of 4 kg cow-1 day-1 in food intake was calculated. In conclusion, the developed software can be a practical tool to assist the producer in making-decision processes

Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia

ArticlePoultry 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

Energetic analysis in compost dairy barn: a case study in southeastern Brazil

Received: February 2nd, 2023 ; Accepted: March 25th, 2023 ; Published: August 16th, 2023 ; Correspondence: [email protected], [email protected] 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

Alternative form to obtain the black globe temperature from environmental variables

ArticleReaching 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

Computational fluids dynamics (CFD) in the spatial distribution of air velocity in prototype designed for animal experimentation in controlled environments

ArticleMaintaining 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