Mecanismos termorreguladores de cabras da raça Saanen -
Data
2007-10-24
Autores
Oliveira, Auriclécia Lopes de [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Foi estudada a eliminação de calor latente e estimado o fluxo térmico total ao sol e à sombra em cabras da raça Saanen mantidas em ambiente tropical, visando determinar importância da termólise evaporativa para esses animais e proporcionar subsídios para o estabelecimento de métodos de manejo em ambiente tropical. A evaporação total foi determinada por processo gravimétrico, usando-se um sistema de pesagem de precisão. A evaporação cutânea foi obtida por determinação direta através de uma cápsula ventilada; e a evaporação respiratória estimada a partir do fluxo térmico entre aparelho respiratório e o ambiente; determinaram-se ainda a estocagem térmica e as trocas convectivas e radiativas. Por ocasião de cada determinação, foram registradas a temperatura retal, a freqüência respiratória e a temperatura da superfície corporal, bem como variáveis ambientais: temperatura e umidade do ar, velocidade do vento e temperatura do globo negro. Foram avaliadas as características morfológicas do pelame (espessura da capa, comprimento médio, densidade numérica e ângulo dos pêlos) para cada animal. As análises estatísticas basearam-se no método dos quadrados mínimos para dados não-balanceados, tendo o modelo linear geral proposto incluído os efeitos: ambiente (fixo), animal (aleatório), interação animal x ambiente e regressão sobre a temperatura do ar, a umidade relativa, a temperatura radiante média, a temperatura da superfície corporal, a temperatura retal, a freqüência respiratória e a idade do animal, além das características morfológicas do pelame, no caso da evaporação cutânea. A termólise evaporativa compreendeu 61,5% da perda de calor para o ambiente, sendo a única via de perda térmica possível ao sol sob temperaturas radiante média acima de 35ºC...
The present work aimed at to study the elimination of latent heat and esteem the total thermal flow to the sun and the shade in Saanen goats in tropical environment, to determine importance of evaporative heat loss these animals and to provide subsidies for the establishment of methods of handling in tropical environment. The total evaporation was determined by means of gravimetrical process, for a weighing system of precision. The cutaneous evaporation was gotten by direct determination, by means of a ventilated capsule; the respiratory evaporation gotten by calculations of heat flow of respiratory device for environment. It was determined still the heat storage and the convective and radiative exchanges. For occasion of each determination, the rectal temperature, respiratory rate and surface temperature of the animal, as well as meteorological data: air temperature, relative humidity, wind speed and black globe temperature were register. The morphologic characteristics of the hair coat (coat thickness, hair length, numerical density and hair angle to skin) had been evaluated for each animal. The statistical analyses were carried through by the lest-squares method for not-balanced data. The considered model included the effect of environment and animal and the covariates: air temperature, relative humidity, mean radiating temperature, surface temperature, rectal temperature, respiratory rate and age of animal, beyond the morphologic characteristics of the hair coat for cutaneous evaporation. Heat loss evaporative understands 62.2% of the heat carried for environment exchange, being the way possible to the sun under radiant temperatures above of 35º...(Complete abstract, click electronic access below)
The present work aimed at to study the elimination of latent heat and esteem the total thermal flow to the sun and the shade in Saanen goats in tropical environment, to determine importance of evaporative heat loss these animals and to provide subsidies for the establishment of methods of handling in tropical environment. The total evaporation was determined by means of gravimetrical process, for a weighing system of precision. The cutaneous evaporation was gotten by direct determination, by means of a ventilated capsule; the respiratory evaporation gotten by calculations of heat flow of respiratory device for environment. It was determined still the heat storage and the convective and radiative exchanges. For occasion of each determination, the rectal temperature, respiratory rate and surface temperature of the animal, as well as meteorological data: air temperature, relative humidity, wind speed and black globe temperature were register. The morphologic characteristics of the hair coat (coat thickness, hair length, numerical density and hair angle to skin) had been evaluated for each animal. The statistical analyses were carried through by the lest-squares method for not-balanced data. The considered model included the effect of environment and animal and the covariates: air temperature, relative humidity, mean radiating temperature, surface temperature, rectal temperature, respiratory rate and age of animal, beyond the morphologic characteristics of the hair coat for cutaneous evaporation. Heat loss evaporative understands 62.2% of the heat carried for environment exchange, being the way possible to the sun under radiant temperatures above of 35º...(Complete abstract, click electronic access below)
Descrição
Palavras-chave
Caprino, Fluxo térmico, Termorregulação, Calor latente, Calor sensível, Estocagem térmica, Goats, Heat flow, Heat storage, Latent heat, sensible heat
Como citar
OLIVEIRA, Auriclécia Lopes de. Mecanismos termorreguladores de cabras da raça Saanen -. 2007. xviii, 78 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2007.