Thermal equilibrium of Nellore cattle in tropical conditions: an investigation of circadian pattern

Página do item simplificado
dc.contributor.authorde Melo Costa, Cíntia Carol [UNESP]
dc.contributor.authorCampos Maia, Alex Sandro [UNESP]
dc.contributor.authorBrown-Brandl, Tami M.
dc.contributor.authorChiquitelli Neto, Marcos [UNESP]
dc.contributor.authorde França Carvalho Fonsêca, Vinicius [UNESP]
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUSDA-ARS US Meat Animal Research Center
dc.date.accessioned2018-12-11T17:37:00Z
dc.date.available2018-12-11T17:37:00Z
dc.date.issued2018-05-01
dc.description.abstractThe aim of this work was to evaluate the diurnal patterns of physiological responses and the thermal regulation of adult Nellore bulls. Six 30-mo-old Nellore bulls (669 ± 65 kg BW) were randomly assigned to four 6-h periods in a Latin Square design such that measurements of each animal cover a 24-h cycle. Meteorological variables (air temperature, relative humidity, local solar irradiance, ultraviolet radiation, wind speed and black globe temperature) were recorded at regular one-minute intervals with an automated weather station. Respiratory rate, ventilation rate, oxygen, carbon dioxide, methane, saturation pressure, air temperature of the exhaled air, saturation pressure in the air leaving the ventilated capsule placed over the animal surface, hair coat, skin surface and rectal temperature were assessed. The thermal equilibrium was determined according to the principles of the first law of thermodynamics using biophysical equations. Animals were evaluated in an area which was protected from solar radiation, rain, and had a range of ambient air temperature between 20.57 ± 0.07 and 30.86 ± 0.07 °C. Percentage of O2 and CO2 in the exhaled air changed moderately (P < 0.0001) throughout the 24 h, which resulted in an average metabolic heat production of 151.45 ± 13.60 W m-2. At the largest thermal gradient (TS - TA; from 24:00–07:00 h), heat transferred by long wave radiation and surface convection corresponded to near 60% of the metabolism. At 11:00 h the ambient temperature approached 29 °C and latent heat became the main way to cool the body. From this time until 17:00 h, cutaneous evaporation represented approximately 53% of total heat loss. In conclusion, results of the present study seem to be a good indicator of lower energy expenditure for body thermal regulation, high heat tolerance and adaptation of Nellore cattle to the tropical environment.en
dc.description.affiliationInnovation Group of Animal Biometeorology (INOBIO) São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences, Access road Prof. Paulo Donato Castellane w/n
dc.description.affiliationUSDA-ARS US Meat Animal Research Center, P.O. Box 166
dc.description.affiliationNucleo de Manejo Racional (MANERA) São Paulo State University (Unesp) School of Natural Sciences and Engineering
dc.description.affiliationUnespInnovation Group of Animal Biometeorology (INOBIO) São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences, Access road Prof. Paulo Donato Castellane w/n
dc.description.affiliationUnespNucleo de Manejo Racional (MANERA) São Paulo State University (Unesp) School of Natural Sciences and Engineering
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipIdFAPESP: 2014/09639-7
dc.description.sponsorshipIdFAPESP: 2014/11170-7
dc.format.extent317-324
dc.identifierhttp://dx.doi.org/10.1016/j.jtherbio.2018.04.014
dc.identifier.citationJournal of Thermal Biology, v. 74, p. 317-324.
dc.identifier.doi10.1016/j.jtherbio.2018.04.014
dc.identifier.issn1879-0992
dc.identifier.issn0306-4565
dc.identifier.scopus2-s2.0-85046702439
dc.identifier.urihttp://hdl.handle.net/11449/179847
dc.language.isoeng
dc.relation.ispartofJournal of Thermal Biology
dc.relation.ispartofsjr0,782
dc.rights.accessRightsAcesso restrito
dc.sourceScopus
dc.subjectAdaptation
dc.subjectLatent heat loss
dc.subjectThermoregulation
dc.subjectZebu cattle
dc.titleThermal equilibrium of Nellore cattle in tropical conditions: an investigation of circadian patternen
dc.typeArtigo

Arquivos

Coleções

Artigos - Biologia e Zootecnia - FEIS