title: Relationship between physical attributes and heat stress in dairy cattle from different genetic groups.
abstract: Dairy cattle raised under harsh conditions have to adapt and prevent heat stress. The aim of this study was to evaluate physical characteristics and their association with heat tolerance in different genetic groups of dairy cattle. Thickness of the skin and coat, length and number of hairs, body measurements, as well as physiological parameters and body temperatures by infrared thermography were determined in 19 Holstein and 19 Girolando (½ and ¾ Holstein) cows. The Holstein cattle were less tolerant to heat stress than Girolando (GH50 and GH75 Holstein), because of the difficulty in dissipating heat due to the larger body size, as well as thicker and longer hairs. The correlations between physical characteristics, physiological parameters, and thermographic measurements prove to be inconsistent among genetic groups and therefore are not predictive of heat tolerance, while the regressions of morphometric characteristics on physiological and thermographic measures were not significant. Thus, the physical characteristics were not good predictors of physiological indices and thermographic temperature and so should not be used.
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. evelynpma@hotmail.com.|Postgraduate Program in Animal Science, Bento Gonçalves Avenue, 7712, 91540-000, Porto Alegre, RS, Brazil. evelynpma@hotmail.com.
authors.forename: Evelyn Priscila München
authors.initials: EP
authors.lastname: Alfonzo
authors.affiliation: Embrapa Dairy Cattle, Juiz de Fora, MG, Brazil.
authors.forename: Marcos Vinicius Gualberto
authors.initials: MV
authors.lastname: Barbosa da Silva
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Darlene
authors.initials: D
authors.lastname: dos Santos Daltro
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.|Faculty of Agroecology, Federal University of Rio Grande-FURG, São Lourenço do Sul, 15, RS, Brazil.
authors.forename: Marcelo Tempel
authors.initials: MT
authors.lastname: Stumpf
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Vanessa Calderaro
authors.initials: VC
authors.lastname: Dalcin
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Giovani
authors.initials: G
authors.lastname: Kolling
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Vivian
authors.initials: V
authors.lastname: Fischer
authors.affiliation: Animal Production Department, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.|Faculty of Agriculture and Veterinary Medicine, University of Brasília, Brasília, DF, Brazil.
authors.forename: Concepta Margaret
authors.initials: CM
authors.lastname: McManus
mesh_terms: D000818:Animals; D049628:Body Size; D001831:Body Temperature; D002417:Cattle / Q000033:anatomy & histology* / Q000235:genetics / Q000502:physiology; D002418:Cattle Diseases / Q000235:genetics / Q000503:physiopathology*; D003612:Dairying; D005260:Female; D014644:Genetic Variation; D006197:Hair / Q000033:anatomy & histology; D006339:Heart Rate; D018882:Heat Stress Disorders / Q000235:genetics / Q000503:physiopathology* / Q000662:veterinary*; D056152:Respiratory Rate; D012867:Skin / Q000033:anatomy & histology
keywords: Coat and cows; Thermography; Tolerance