What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?

Detalhes bibliográficos
Autor(a) principal: Nascimento,Fernanda Gatti de Oliveira
Data de Publicação: 2019
Outros Autores: Aguiar,Hellen Cris Pinto, Rodrigues,Gustavo Moya, Guimarães,Ednaldo Carvalho, Nascimento,Mara Regina Bueno de Mattos
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Ciência Rural
Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000100652
Resumo: ABSTRACT: The aim of this study was to determine among nine temperature-humidity index (THI) equations, the one that best represents the effects of heat stress on crossbred dairy calves reared in a tropical environment. Twelve male and female calves, aged 20 to 60 days, and raised in a tropical pen were evaluated. Respiratory (RR) and heart rates (HR), rectal (RT), body surface (BST), dry bulb (Tdb) and wet bulb (Tbw) temperatures, partial vapor pressure (Pv), relative humidity (RH) and dew point temperature (Tpo) were quantified in the morning and afternoon. Nine THI equations were calculated. The highest correlation between physiological variables and this was used to select the best THI equation. Averages for nine THI equations, Tdb, Twb, Pv, Tdp, RR, HR, RT, and BST were higher in the afternoon than in the morning, whereas that for RH was the opposite. The highest values for RT occurred at temperatures above 26.4°C and when humidity was below 55.5%. The Tdb and Pv correlations with RR (0.697 and 0.707), RT (0.703 and 0.706) and BST (0.818 and 0.817) were significant and positive, whereas the RH correlations with the same physiological variables were significant and negative (-0.622, -0.590 and -0.638, respectively). The best index was the THI sensible heat-based ( T H I = 3.43 + 1.058 x T d b - 0.293 x R H + 0.0164 x T d b x R H + 35.7), which was significantly correlated with RR (r=0.668 and r²=0.446), HR (r=0.259 and r²=0.067), RT (r=0.693 and r²=0.479) and BST (r=0.807 and r²=0.650). In conclusion, the THI sensible heat-based equation best represents the effects of heat stress on crossbred dairy calves reared in a tropical environment.
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spelling What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?cattlecomfortdairythermal indexABSTRACT: The aim of this study was to determine among nine temperature-humidity index (THI) equations, the one that best represents the effects of heat stress on crossbred dairy calves reared in a tropical environment. Twelve male and female calves, aged 20 to 60 days, and raised in a tropical pen were evaluated. Respiratory (RR) and heart rates (HR), rectal (RT), body surface (BST), dry bulb (Tdb) and wet bulb (Tbw) temperatures, partial vapor pressure (Pv), relative humidity (RH) and dew point temperature (Tpo) were quantified in the morning and afternoon. Nine THI equations were calculated. The highest correlation between physiological variables and this was used to select the best THI equation. Averages for nine THI equations, Tdb, Twb, Pv, Tdp, RR, HR, RT, and BST were higher in the afternoon than in the morning, whereas that for RH was the opposite. The highest values for RT occurred at temperatures above 26.4°C and when humidity was below 55.5%. The Tdb and Pv correlations with RR (0.697 and 0.707), RT (0.703 and 0.706) and BST (0.818 and 0.817) were significant and positive, whereas the RH correlations with the same physiological variables were significant and negative (-0.622, -0.590 and -0.638, respectively). The best index was the THI sensible heat-based ( T H I = 3.43 + 1.058 x T d b - 0.293 x R H + 0.0164 x T d b x R H + 35.7), which was significantly correlated with RR (r=0.668 and r²=0.446), HR (r=0.259 and r²=0.067), RT (r=0.693 and r²=0.479) and BST (r=0.807 and r²=0.650). In conclusion, the THI sensible heat-based equation best represents the effects of heat stress on crossbred dairy calves reared in a tropical environment.Universidade Federal de Santa Maria2019-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000100652Ciência Rural v.49 n.1 2019reponame:Ciência Ruralinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM10.1590/0103-8478cr20180132info:eu-repo/semantics/openAccessNascimento,Fernanda Gatti de OliveiraAguiar,Hellen Cris PintoRodrigues,Gustavo MoyaGuimarães,Ednaldo CarvalhoNascimento,Mara Regina Bueno de Mattoseng2019-02-06T00:00:00ZRevista
dc.title.none.fl_str_mv What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
title What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
spellingShingle What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
Nascimento,Fernanda Gatti de Oliveira
cattle
comfort
dairy
thermal index
title_short What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
title_full What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
title_fullStr What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
title_full_unstemmed What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
title_sort What is the best temperature-humidity index equation to indicate heat stress in crossbred dairy calves in a tropical environment?
author Nascimento,Fernanda Gatti de Oliveira
author_facet Nascimento,Fernanda Gatti de Oliveira
Aguiar,Hellen Cris Pinto
Rodrigues,Gustavo Moya
Guimarães,Ednaldo Carvalho
Nascimento,Mara Regina Bueno de Mattos
author_role author
author2 Aguiar,Hellen Cris Pinto
Rodrigues,Gustavo Moya
Guimarães,Ednaldo Carvalho
Nascimento,Mara Regina Bueno de Mattos
author2_role author
author
author
author
dc.contributor.author.fl_str_mv Nascimento,Fernanda Gatti de Oliveira
Aguiar,Hellen Cris Pinto
Rodrigues,Gustavo Moya
Guimarães,Ednaldo Carvalho
Nascimento,Mara Regina Bueno de Mattos
dc.subject.por.fl_str_mv cattle
comfort
dairy
thermal index
topic cattle
comfort
dairy
thermal index
description ABSTRACT: The aim of this study was to determine among nine temperature-humidity index (THI) equations, the one that best represents the effects of heat stress on crossbred dairy calves reared in a tropical environment. Twelve male and female calves, aged 20 to 60 days, and raised in a tropical pen were evaluated. Respiratory (RR) and heart rates (HR), rectal (RT), body surface (BST), dry bulb (Tdb) and wet bulb (Tbw) temperatures, partial vapor pressure (Pv), relative humidity (RH) and dew point temperature (Tpo) were quantified in the morning and afternoon. Nine THI equations were calculated. The highest correlation between physiological variables and this was used to select the best THI equation. Averages for nine THI equations, Tdb, Twb, Pv, Tdp, RR, HR, RT, and BST were higher in the afternoon than in the morning, whereas that for RH was the opposite. The highest values for RT occurred at temperatures above 26.4°C and when humidity was below 55.5%. The Tdb and Pv correlations with RR (0.697 and 0.707), RT (0.703 and 0.706) and BST (0.818 and 0.817) were significant and positive, whereas the RH correlations with the same physiological variables were significant and negative (-0.622, -0.590 and -0.638, respectively). The best index was the THI sensible heat-based ( T H I = 3.43 + 1.058 x T d b - 0.293 x R H + 0.0164 x T d b x R H + 35.7), which was significantly correlated with RR (r=0.668 and r²=0.446), HR (r=0.259 and r²=0.067), RT (r=0.693 and r²=0.479) and BST (r=0.807 and r²=0.650). In conclusion, the THI sensible heat-based equation best represents the effects of heat stress on crossbred dairy calves reared in a tropical environment.
publishDate 2019
dc.date.none.fl_str_mv 2019-01-01
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000100652
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000100652
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/0103-8478cr20180132
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv text/html
dc.publisher.none.fl_str_mv Universidade Federal de Santa Maria
publisher.none.fl_str_mv Universidade Federal de Santa Maria
dc.source.none.fl_str_mv Ciência Rural v.49 n.1 2019
reponame:Ciência Rural
instname:Universidade Federal de Santa Maria (UFSM)
instacron:UFSM
instname_str Universidade Federal de Santa Maria (UFSM)
instacron_str UFSM
institution UFSM
reponame_str Ciência Rural
collection Ciência Rural
repository.name.fl_str_mv
repository.mail.fl_str_mv
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