Fecha/hora: 03/06/2024 21:10:50

Biblioteca(s): 	INIA Las Brujas.	
Fecha corriente: 	21/02/2014	
Fecha de la última actualización: 	03/10/2019	
Autoria: 	RAVAGNOLO, O.; MISZTAL, I.	
Afiliación: 	OLGA RAVAGNOLO GUMILA, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; I. MISZTAL, University of Georgia, United States.	
Título: 	Effect of heat stress on nonreturn rate in holstein cows: Genetic analyses.	
Año de publicación: 	2002	
Fuente/Imprenta: 	Journal of Dairy Science, 2002, 85 (11): 3092-3100.	
ISSN: 	0022-0302	
DOI: 	10.3168/jds.S0022-0302(02)74396-8	
Idioma: 	Inglés	
Notas: 	Article history: Received August 13, 2001. / Accepted October 16, 2002.	
Contenido: 	ABSTRACT.
The genetic component in heat tolerance for nonreturn rate in Holsteins was estimated using an animal linear model augmented by a random regression on a temperature-humidity index (THI). Data consisted of 18,059 nonreturn rates at 45, 60, and 90 d after insemination and 81,674 first-parity test-day milk yields from 78 herds in Florida. The THI on the day of insemination or test day was added to each record. Only first-insemination records were used. The model for nonreturn rate included the effects of herd-year-season, age, days in milk, milk yield, THI as a covariable, regular additive effect, and random regression on THI for heat-tolerance additive effect. With a single-trait model, heritability estimates for NR45, NR60, and NR90 at THI = 70 for first-lactation cows were 0.006, 0.014, and 0.053, respectively. Genetic correlation between regular NR90 and heat tolerance was -0.95. A bivariate analysis for NR90 and test-day milk production yielded a correlation between regular merit and heat tolerance for NR90 of -0.35, substantially lower than by the univariate model, indicating a bias in the univariate estimates caused by ignored selection. The regular genetic correlation between NR90 and milk yield was -0.41. Genetic correlation between heat tolerance for NR90 and heat tolerance for milk yield was -0.04, indicating the need to separate selection.
© Copyright 2017 Elsevier B.V., All rights reserved.	
Palabras-Clave: 	Dairy cattle; Heat stress; Nonreturn rate; Temperature-humidity index.	
Categoría del tema: 	--	
URL: 	http://www.ainfo.inia.uy/digital/bitstream/item/13409/1/Jr.Dairy-Science.-2002.-1-s2.0-S0022030202743968-main.pdf
https://www.journalofdairyscience.org/article/S0022-0302(02)74396-8/pdf	
Registro original: 	INIA Las Brujas (LB)	
Ejemplares: 	LB - (12855-1) - PXI - AP - DD - PP/JR. DAIRY SCIENCE/2002 -  -  - DIS