ABSTRACT
Exposure of goats to high air temperatures can induce physiological and behavioral adjustments, increasing the dissipation of excess body heat in the latent form, and intensification of the use of these thermoregulatory tools can result in physiological and productive damage to animals. With this, the objective of the research was to quantify the levels of thermal stress and the sensible and latent heat losses of Boer crossbred goats submitted to different air temperatures, in a climatic chamber. Six male crossbred goats of the Boer breed, with an average weight of 25.06 ± 4.43 kg and mean age of six months, were grouped using a completely randomized design, with three treatments (air temperatures of the 26, 30 and 34 °C, respectively) and six replicates (animals) with 68% relative humidity. The temperature and relative humidity of the air were collected to calculate the temperature and humidity index (THI) and heat exchanges. Were collected the physiological responses rectal temperature (RT) and surface (ST) and respiratory rate (RF), with these data were estimated the heat exchanges by radiation (L), convection (Cr), total sensitive (Gs), latent of the respiratory tract (Er), cutaneous (Ec), total latent (Et) and total heat exchange (Wt). It was found that the THI values were classified as thermal comfort, moderate stress and very stressful, respectively, in the three conditions evaluated. With the increase in AT, the animals significantly increased (P < 0.05) the RT, ST and RF, and consequently reduced sensitive heat exchanges, from 38 to 8%, and increased latent heat exchanges, from 62 to 92%, when compared air temperatures of 26 and 34 °C, respectively. Physiological responses showed a significant negative (P < 0.05) correlation with sensitive heat exchanges and a positive correlation with latent heat exchanges. In very stressful thermal conditions, the animals lost almost all of the excess metabolic heat by latent means (skin and respiratory tract).
Subject(s)
Body Temperature Regulation , Goats/physiology , Heat-Shock Response/physiology , Animals , Climate , Heat Stress Disorders/physiopathology , Heat Stress Disorders/veterinary , Humidity , Hybridization, Genetic , Male , Models, Biological , Respiratory Rate , TemperatureABSTRACT
The objective of this study was to evaluate the physiological responses, ethology, and ingestive behavior of female Morada Nova sheep kept in a thermoneutral environment, after thermal stress and after consuming water with different levels of salinity. Thirty-six Morada Nova females with a mean age of 10.0 ± 2.0 months and a mean weight of 25.0 ± 3.0 kg were evaluated and distributed in a climatic chamber. The experimental design was completely randomized, with a factorial scheme of 2 (air temperature (AT)) × 3 (salinity levels (SLs)) and six replications. The sheep's physiological responses, ethology (day/night), and ingestive behavior were evaluated while they were subjected to ATs of 26.0 and 32.0 °C and SLs of 3.0, 6.0, and 9.0 dS/m. With elevation in AT, the animals experienced increased (P < 0.05) rectal temperatures (RTs), respiratory rates (RFs), and surface temperatures (STs) and exhibited reduced (P < 0.05) heart rates (HRs). When consuming water with an SL of 9.0 dS/m, a HR reduction (P < 0.05) was observed. Sleep behavior increased (P < 0.05) with the increase in SL during the day. Sleeping and drinking behaviors increased (P < 0.05), and the time of inactivity was reduced (P < 0.05) during the nocturnal period with increased SLs. With increased SLs, sheep consumed more water (P < 0.05) and reduced (P < 0.05) the number of regurgitated ruminal boluses per day (NRBD). Under the conditions of thermal stress (32.0 °C), sheep need to make physiological adjustments to maintain homeothermy. Water consumption of SLs up to 9.0 dS/m causes a higher state of dormancy in female Morada Nova sheep.
Subject(s)
Salinity , Water , Animals , Ethology , Female , Random Allocation , Sheep , Sheep, Domestic , TemperatureABSTRACT
Nos últimos anos, o crescimento da agricultura brasileira tem forçado vários setores a se adequarem aos padrões produtivos com o intuito de se manterem competitivos, frente ao processo de globalização econômica. Nesse contexto, as fábricas de ração avícola tendem a buscar novas alternativas que favoreçam a produção e reduzam custos sem afetar a qualidade do produto final. Entre essas alternativas, destaca-se o uso de silos verticais por facilitar o processo de confecção das rações e eliminar os grandes depósitos horizontais. Diante dessa possibilidade, objetivou-se, com a presente pesquisa, estudar as tensões nas paredes em conformação ziguezague de um silo metálico prismático 2m x 1m e comparar os resultados obtidos com teorias e normas. Para o cálculo das tensões, utilizaram-se os métodos simplificados de Ravenet e Troitsky. Para a obtenção dos esforços reais nas paredes, utilizaram-se extensômetros elétricos. Dessa forma, conclui-se que, tanto a teoria de Ravenet quanto de Troistky, podem ser recomendadas para o dimensionamento de silos prismáticos por apresentarem boa aproximação com valores experimentais.
Recently Brazil has undergone agricultural growth that has forced several sectors to adjust their business structure to maintain competitiveness within the process of economic globalization. In this context, the poultry production has focused on new alternatives to increase productivity and reduce costs without affecting the quality of the final product. Among these alternatives, the use of vertical silos due to their capacity and ease of accurate feed ingredient rationing and eliminate large horizontal warehouses. The present research has focused on the stresses in rectangular, hopper bottom bins with a unique zigzag corrugation. The model bin was 2m x 1m with a hopper and the stresses obtained were compared to theories and standards. The stresses were estimated using Ravenet and Troitsky's simplified methods and compared to the experimental results. Strain gauges were used to obtain data on the stress within the bin walls. One concluded that either Ravenet or Troitsky's theory may be recommended for the design of rectangular silos since they provide a high level of accuracy compared to experimental values.
ABSTRACT
O conhecimento das propriedades físicas e de fluxo dos produtos é de extrema importância no que se refere ao seu manuseio e processamento. Com a correta aplicação desses conhecimentos, é possível dimensionar de forma racional os sistemas de transporte e armazenagem utilizados, prevendo, assim, o tipo de fluxo ideal para cada operação. Este trabalho teve como objetivo determinar as propriedades físicas e de fluxo de três diferentes rações avícolas e avaliar suas influências nas características geométricas de tremonhas. Na obtenção dos dados, foi utilizado o aparelho de cisalhamento direto de translação (célula de cisalhamento de Jenike) e duas superfícies de parede: aço liso e rugoso. Para determinar o índice de fluxo (ff c) e o diâmetro mínimo do orifício de descarga (D), adotou-se a metodologia de Jenike enquanto que para o ângulo mínimo de inclinação da tremonha cônica, utilizou-se a metodologia de Enstad. Com base nos resultados obtidos, conclui-se que as Rações A e B foram classificadas como produtos coesivos enquanto que a Ração C apresentou os menores ângulos de inclinação da tremonha e maiores diâmetros de orifício de descarga.
The knowledge about the physical and flow properties of industrial powders is very important to their handling and processing. With the right application of this information, it's possible to design conveyors and storage systems to predict the ideal kind of flow for each operation. This work had the objective to determinate the physical and flow properties of different kinds of poultry rations and to evaluate their influences on geometric characteristics of hoppers. For that, it was used the direct shear apparatus based on Jenike shear cell and two friction surfaces: smooth and rough steel walls. To determinate the index flow (ff c) and minimum hopper opening diameter (D), was used the Jenike's methodology. For the minimum conical hopper angle, was used the mathematical method advised by British Standard BMHB. With the basis on obtained results, it's possible to affirm that A and B poultry rations were classified as cohesive flow while the B poultry ration had the minors conical hopper angle and the higher hopper opening diameter.
