Efeitos da temperatura e da movimentação do ar sobre o isolamento térmico do velo de ovinos em câmara climática
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Data
2009-01-01
Autores
Maia, Alex Sandro Campos
Silva, Roberto Gomes da [UNESP]
Andrade, Patrícia de Cássia
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
Foram utilizados dez ovinos da raça Corriedale - cinco machos e cinco fêmeas com pesos entre 52,2 e 87,6 kg - com o objetivo de avaliar o efeito da combinação da movimentação do ar (0 e 5,0 m/s) com a temperatura do ar (25, 30 e 40ºC) sobre a temperatura retal (T R, ºC), da epiderme (T E, ºC), da superfície do velo (T V, ºC) e do interior do velo (T I, ºC) e a espessura do velo (E V, cm) e suas relações com o isolamento térmico do velo. A presença de vento não teve efeito sobre as variáveis estudadas, o que sugere que fluxo de ar (<5,0 m/s) paralelo ao eixo corporal do animal tem pouco efeito sobre o isolamento térmico do velo, independentemente da temperatura do ar, que se mostrou altamente correlacionada, de forma positiva, com as temperaturas retal, do velo, do interior do velo e da epiderme. Sob temperaturas inferiores a 30ºC, a transferência de calor através do velo ocorreu via condução e convecção livre, enquanto sob altas temperaturas (>40ºC) o fluxo de calor sensível não foi significativa.
Ten Corriedale sheep were evaluated, five males and five females with 52.2 to 87.6 kg of body weight, to evaluate the effect of air velocity (0 and 5 m/s) and temperature (25, 30 and 40ºC) on rectal temperature (T R, ºC), skin temperature (T E, ºC), fleece surface temperature (T V, ºC), temperature inside the fleece (T I, ºC), and fleece thickness (E V, cm) and their relationship with fleece thermal insulation. The results showed that air velocity did not affect the studied traits, suggesting that airflow <5.0 m/s parallel to the fleece had little effect on fleece thermal insulation, regardless the air temperature. Air temperature was highly correlated with T R, T E, T I and T V. Under air temperatures below 30°C, the heat transfer through the fleece was dominated by conduction and free convection, while under high temperatures (>40°C), the sensible heat flow was not significant.
Ten Corriedale sheep were evaluated, five males and five females with 52.2 to 87.6 kg of body weight, to evaluate the effect of air velocity (0 and 5 m/s) and temperature (25, 30 and 40ºC) on rectal temperature (T R, ºC), skin temperature (T E, ºC), fleece surface temperature (T V, ºC), temperature inside the fleece (T I, ºC), and fleece thickness (E V, cm) and their relationship with fleece thermal insulation. The results showed that air velocity did not affect the studied traits, suggesting that airflow <5.0 m/s parallel to the fleece had little effect on fleece thermal insulation, regardless the air temperature. Air temperature was highly correlated with T R, T E, T I and T V. Under air temperatures below 30°C, the heat transfer through the fleece was dominated by conduction and free convection, while under high temperatures (>40°C), the sensible heat flow was not significant.
Descrição
Palavras-chave
wind, sensible heat, Sheep, vento, Calor sensível, Ovinos
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 38, n. 1, p. 104-108, 2009.