| Registro completo |
| Provedor de dados: |
R. Bras. Zootec.
|
| País: |
Brazil
|
| Título: |
Effective thermal conductivity of the hair coat of Holstein cows in a tropical environment
|
| Autores: |
Maia,Alex Sandro Campos
Silva,Roberto Gomes da
Souza Junior,João Batista Freire de
Silva,Rosiane Batista da
Domingos,Hérica Girlane Tertulino
|
| Data: |
2009-11-01
|
| Ano: |
2009
|
| Palavras-chave: |
Hair coat
Holstein cows
Thermal conductivity
|
| Resumo: |
The objective of the present study was to assess the effective thermal conductivity of the hair coat (k ef, mW.m-1.K-1) of Holstein cows in a tropical environment, as related to conduction and radiation in the absence of free convection. The average k ef was 49.72 mW.m-1.K-1, about twice the conductivity of the air (26 mW.m-1.K-1) and much less than that of the hair fibres (260 mW.m-1.K-1). The low k ef values were attributed mainly to the small cross area of individual hairs, ρef/ρf (17.2% and 21.3% for black and white hairs, respectively). White coats were denser, with longer hairs and significantly higher k ef (53.15 mW.m-1.K-1) than that of the black hairs (49.25 mW.m-1.K-1). The heritability coefficient of the effective thermal conductivity was calculated as h²=0.18 the possibility was discussed of selecting cattle for increased heat transfer through the hair coat.
|
| Tipo: |
Info:eu-repo/semantics/article
|
| Idioma: |
Inglês
|
| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982009001100022
|
| Editor: |
Sociedade Brasileira de Zootecnia
|
| Relação: |
10.1590/S1516-35982009001100022
|
| Formato: |
text/html
|
| Fonte: |
Revista Brasileira de Zootecnia v.38 n.11 2009
|
| Direitos: |
info:eu-repo/semantics/openAccess
|
