Data/hora: 13/06/2024 00:24:42

Biblioteca(s): 	Embrapa Gado de Leite.	
Data corrente: 	06/01/2020	
Data da última atualização: 	06/02/2024	
Autoria: 	SANTANA JUNIOR, M. L.; PEREIRA, R. J.; BIGNARDI, A. B.; EL FARO, L.; PIRES, M. de F. A.; ANDRADE, R. G.; PEREZ, B. C.; BRUNELI, F. A. T.; PEIXOTO, M. G. C. D.	
Afiliação: 	MARIA DE FATIMA AVILA PIRES, CNPGL; RICARDO GUIMARAES ANDRADE, CNPGL; FRANK ANGELO TOMITA BRUNELI, CNPGL; MARIA GABRIELA CAMPOLINA D PEIXOTO, CNPGL.	
Título: 	Dual-purpose Guzerá cattle exhibit high dairy performance under heat stress.	
Ano de publicação: 	2020	
Fonte/Imprenta: 	Journal of Animal Breeding and Genetics, v. 137, p. 486-494, 2020.	
DOI: 	https://doi.org/10.1111/jbg.12450	
Idioma: 	Inglês	
Conteúdo: 	The present study evaluated the heat stress response pattern of dual-purpose Guzerá cattle for test-day (TD) milk yield records of first lactation and estimated genetic parameters and trends related to heat stress. A total of 31,435 TD records from 4,486 first lactations of Guzerá cows, collected between 1986 and 2012, were analysed. Two random regression models considered days in milk (DIM) and/or temperature × humidity-dependent (THI) covariate. Impacts of -0.037, -0.019 and -0.006 kg/day/THI for initial and intermediate stages of lactation were observed when considering the mean maximum daily temperature and humidity to calculate THI. Heritability estimates ranged from 0.16 to 0.35 throughout lactation and THI values, suggesting the possibility to expect gains from selection for such trait. The variable trajectory of breeding values for dual-purpose Guzerá sires in response to changes in THI values confirms that the genotype × environment interaction due to heat stress can have some effect on TD milk yield. Despite the high dairy performance of Guzerá cattle under heat stress, estimated genetic trends showed a progressive reduction in heat tolerance. Therefore, new strategies should be adopted to prevent negative impacts of heat stress over milk production in Guzerá animals in future.	
Palavras-Chave: 	Genotype-by-environment interaction; Random regression; Reaction norm.	
Thesaurus Nal: 	Milk production; Zebu.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Gado de Leite (CNPGL)	
Exemplares: 	CNPGL - (24940-1) - UPC - AP - DD -  -  -  - DIS