Sensible and latent heat loss from the body surface of Holstein cows in a tropical environment

Sensible and latent heat loss from the body surface of Holstein cows in a tropical environment

The general principles of the mechanisms of heat transfer are well known, but knowledge of the transition between evaporative and non-evaporative heat loss by Holstein cows in field conditions must be improved, especially for low-latitude environments. With this aim 15 Holstein cows managed in open...

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Bibliographic Details
Published in:International journal of biometeorology Vol. 50; no. 1; pp. 17 - 22
Main Authors: Maia, A.S.C, daSilva, R.G, Battiston Loureiro, C.M
Format: Journal Article
Language:English
Published: United States Springer Nature B.V 01-09-2005
Subjects:
Air temperature
Animals
Body Temperature Regulation - physiology
Brazil
Cattle
Cattle - physiology
Evaporation
Female
Heat transfer
Humidity
Latent heat
Mathematical models
Models, Biological
Pasture
Sensible heat
Skin Physiological Phenomena
Temperature
Tropical Climate
Tropical environments
Ventilation
Brazil
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Summary:The general principles of the mechanisms of heat transfer are well known, but knowledge of the transition between evaporative and non-evaporative heat loss by Holstein cows in field conditions must be improved, especially for low-latitude environments. With this aim 15 Holstein cows managed in open pasture were observed in a tropical region. The latent heat loss from the body surface of the animals was measured by means of a ventilated capsule, while convective heat transfer was estimated by the theory of convection from a horizontal cylinder and by the long-wave radiation exchange based on the Stefan-Boltzmann law. When the air temperature was between 10 and 36°C the sensible heat transfer varied from 160 to -30 W m-2, while the latent heat loss by cutaneous evaporation increased from 30 to 350 W m-2. Heat loss by cutaneous evaporation accounted for 20-30% of the total heat loss when air temperatures ranged from 10 to 20°C. At air temperatures >30°C cutaneous evaporation becomes the main avenue of heat loss, accounting for approximately 85% of the total heat loss, while the rest is lost by respiratory evaporation.
Bibliography:http://dx.doi.org/10.1007/s00484-005-0267-1
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0020-7128
1432-1254
DOI:10.1007/s00484-005-0267-1