Fecha/hora: 31/05/2024 23:03:10

Biblioteca(s): 	INIA Treinta y Tres.	
Fecha corriente: 	11/01/2021	
Fecha de la última actualización: 	11/01/2021	
Autoria: 	NEGRI, R.; AGUILAR, I.; FELTES, G. L.; MACHADO, J. D.; NETO, J. B.; COSTA-MAIA, F. M.; COBUCI, J. A.	
Afiliación: 	RENATA NEGRI, Department of Animal Science, Federal University of Rio Grande of Sul, Porto Alegre.; IGNACIO AGUILAR GARCIA, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; GIOVANI LUIS FELTES, Department of Animal Science, Federal University of Rio Grande of Sul, Porto Alegre; JULIANA DEMENTSHUK MACHADO, Department of Animal Science, Federal University of Rio Grande of Sul, Porto Alegre.; JOSÉ BRACCINI NETO, Department of Animal Science, Federal University of Rio Grande of Sul, Porto Alegre, RS, Brazil.; FABIANA MARTINS COSTA-MAIA, Department of Animal Science, Federal Technological University of Paraná, Brazil; JAIME ARAÚJO COBUCI, Department of Animal Science, Federal University of Rio Grande of Sul, Porto Alegre, RS,Brazil.	
Título: 	Inclusion of bioclimatic variables in genetic evaluations of dairy cattle.[Open Access].	
Año de publicación: 	2021	
Fuente/Imprenta: 	Animal Bioscience [Asian-Australasian Journal of Animal Sciences], Volume 34, Issue 2, February 2021, Pages 163-171. Doi: https://doi.org/10.5713/ajas.19.0960	
ISSN: 	1976-5517	
DOI: 	10.5713/ajas.19.0960	
Idioma: 	Inglés	
Notas: 	Article history: Submitted Dec 16, 2019 / Revised Mar 27, 2020 / Accepted Apr 28, 2020.
Corresponding Author: rn.negri@yahoo.com	
Contenido: 	Objective: Considering the importance of dairy farming and the negative effects of heat stress, more tolerant genotypes need to be identified. The objective of this study was to investigate the effect of heat stress via temperature-humidity index (THI) and diurnal temperature variation (DTV) in the genetic evaluations for daily milk yield of Holstein dairy cattle, using random regression models.
Methods: The data comprised 94,549 test-day records of 11,294 first parity Holstein cows from Brazil, collected from 1997 to 2013, and bioclimatic data (THI and DTV) from 18 weather stations. Least square linear regression models were used to determine the THI and DTV thresholds for milk yield losses caused by heat stress. In addition to the standard model (SM, without bioclimatic variables), THI and DTV were combined in various ways and tested for different days, totaling 41 models.
Results: The THI and DTV thresholds for milk yield losses was THI = 74 (?0.106 kg/d/THI) and DTV = 13 (?0.045 kg/d/DTV). The model that included THI and DTV as fixed effects, considering the two-day average, presented better fit (?2logL, Akaike information criterion, and Bayesian information criterion). The estimated breeding values (EBVs) and the reliabilities of the EBVs improved when using this model.
Conclusion: Sires are re-ranking when heat stress indicators are included in the model. Genetic evaluation using the mean of two days of THI and DTV as fixed effect, improved EBVs and EBVs reliability.	
Palabras-Clave: 	DAIRY CATTLE; DIURNAL TEMPERATURE VARIATION; GANADO DE LECHE; HEAT STRESS; RANDOM REGRESSION; TEMPERATURE-HUMIDITY INDEX.	
Categoría del tema: 	L01 Ganadería	
URL: 	http://www.ainfo.inia.uy/digital/bitstream/item/14923/1/ajas-19-0960.pdf
https://www.animbiosci.org/journal/view.php?number=24526	
Registro original: 	INIA Treinta y Tres (TT)	
Ejemplares: 	TT - (103215-1) - PXI - AP - DD - PP/ANIMAL -BIOSCIENCE/2021 -  -  - DIS