No abstract

The facilities for laying hens should be designed to provide thermal comfort and satisfactory luminosity for the production of quality eggs. The objective of this study was to evaluate the spatial behavior of thermal conditions and light intensity of facilities for laying hens with vertical cages naturally conditioned during winter and summer. Air temperature, air relative humidity and light intensity data were collected in 75 points distributed evenly through the longitudinal direction of the installation in three tiers of cages (first, third and sixth). Each point represented a set of coordinates (x, y, z), being the x-axis the lines (L1, L2, L3, L4, L5), y-axis the sections (S1, S2, S3, S4, S5) and z-axis the tiers (N1, N2, N3). The spatial behavior of the thermal conditions of the facility was held during the coldest period of winter and the warmest period of summer. The experimental design was completely randomized in a factorial scheme. In the winter, the temperature showed homogeneous behavior among sections and variable among lines. In the summer, the spatial variability of temperature and humidity was more accentuated than in the winter, mainly among tiers. For both seasons, the center of the facility presented lower light intensity than the lateral. From the spatial behavior of the thermal conditions of the facility laying hens, it is possible to verify the magnitude and variability of temperature, relative humidity and light intensity, identify vulnerable and deficit thermal regions and contribute to decision-making related to thermal conditioning and luminosity of the facility.

The objective of this study was to evaluate the thermal comfort of growing and finishing pigs affected by the different constructive typologies of the installations regarding the floor and lateral partitions. Were evaluated the following pen types: pen with water pit, pen with partially slotted floor on the sides, and pen with partially slotted floor on the sides and in the center of the facilities. The following thermal variables were measured: dry bulb temperature, black globe temperature, relative humidity, and air velocity. Based on these data, the temperature and humidity index, the temperature index of the globe and humidity, and the specific enthalpy were calculated. The pen with a water pit showed higher average relative air humidity and lower black globe temperature compared to the other pens. In the hottest period of the day, the temperature index of the globe and humidity presented mean values above that recommended for adult pigs, although there were no differences between pens. This indicates that animals, irrespective of the type of pen used, have suffered from thermal stress, which most likely affected their performance.

The objective of this review was to address the stress effects on meat quality considering the main attributes that involve meat quality. Animal protein production has been increasing with global demand for meat with meat quality a major concern, especially for more demanding consumers who are looking for quality products to meet their needs. The quality of the meat is the result of what happened to the animal throughout the production chain, that is, good rearing conditions result in a better meat quality. Different types of stress can be harmful to animals due to inadequate or improper animal handling on farms, inadequate transport conditions, poorly maintained trucks and roads, and conditions that agitate animals can lead to bruising, thermal stress. The stress in animals occurs when they are in adverse conditions and can significantly compromise meat quality loss. As an example, stress can significantly affect meat quality parameters as drip loss (DL), meat color, change ultimate pH and cause meat anomalies. Among the main parameters of evaluation used for meat quality are color, characterized by luminosity (L*, a*, b*), lipid and protein oxidation, pH, water holding capacity (WHC) and softness. Producing and processing high-quality meat is a challenge since it is necessary to apply methods that promote comfort in a complete sense, in a way that minimizes inducing significant stress. Based on the results presented it is remarkable that stress alters the meat quality, compromising the main attributes that involve it, like color, pH, WHC, Warner-Bratzler shear force (WBSF), lipid oxidation, among others andis necessary to avoid or reduce stress caused during the production of the animals to ensure a high-quality meat, resulting in greater profitability for the producer.

No abstract

External egg quality is an essential parameter of egg production as it relates directly to economic losses. This study evaluated the spatial variability of external egg quality in five naturally ventilated caged vertical aviaries. Differences caused by bird age and thermal and luminous variability within aviaries during winter and summer were analyzed. Data on aviary air temperature, relative humidity, light intensity, and external egg quality were collected at evenly distributed points along the aviary length within three levels of cages. The experimental design was completely randomized in a factorial scheme. In the summer, the highest air temperature and lowest relative humidity were found in central cages, mainly in upper center cages; hens produced eggs with a lower weight and shape index in this area. Similar results were obtained in the winter. In the summer, eggs with lower shell weight and thickness were also produced by hens housed in the central cages, but in the winter, the opposite result was obtained. This study of the spatial variability of external egg quality proved efficient in detecting areas within an aviary with poor quality eggs; improvements to design and management in these areas could help management improve production efficiency and contribute to a sustainable egg supply.

No abstract

RESUMO:As estruturas de controle comumente utilizadas nas tomadas de água dos canais de irrigação não permitem a distribuição da quantidade correta de água, favorecendo o desperdício e, consequentemente, reduzindo a eficiência no uso da água. O objetivo deste trabalho foi determinar o desempenho de um regulador automático de vazão no controle da vazão derivada. Para tanto, um exemplar do equipamento, construído em fibra de vidro, foi instalado na lateral de um canal de concreto do Laboratório de Hidráulica da Universidade Federal de Viçosa, em Viçosa-MG. O equipamento foi avaliado em toda a sua faixa de operação, sendo que, em cada regulagem prefixada, determinou-se a vazão derivada com o nível da água a montante variando de 0,30 a 0,45 m. A variação média na vazão do regulador, considerando toda a sua faixa de operação, foi de ± 2,3% em relação às vazões médias fornecidas pelo equipamento em cada regulagem. A amplitude de variação na vazão fornecida foi pequena em relação aos equipamentos usualmente empregados no controle de vazão, em canais de irrigação, demonstrando que o regulador automático de vazão é um equipamento apropriado para a distribuição de água em redes de canais. PALAVRAS-CHAVE:automação hidráulica, comportas hidráulicas, condutos livres. PERFORMANCE OF AN AUTOMATIC DISCHARGE REGULATOR FOR IRRIGATION CHANNELS ABSTRACT:The control structures commonly used in irrigation channels water intakes are inefficient in delivering the correct water volume to crops, collaborating to water waste and, hence, reducing the water use efficiency. The objective of this work was to determine the performance of an automatic discharge regulator in the control of the supplied discharge. The regulator was made of fiberglass and its evaluation was accomplished in a concrete channel belonging to the Hydraulic Laboratory of the Federal University of Viçosa, in Viçosa, state of Minas Gerais, Brazil. The evaluation was performed for all equipment discharge regulation options. In each regulation, the supplied discharge was determined for the upstream water level changing from 0.30 to 0.45 m. The regulator discharge mean variation, with regard to all regulation options, was of ± 2.3% of the mean discharge supplied by the equipment in each regulation option. The discharge variation of the developed equipment was smaller than the discharge variation of the structures commonly used to control the discharge in channels, showing that the automatic flow regulator is a good alternative to regulate discharges in open channels.