An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments

An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments

Heterogeneity of variance in Brazilian herd environments was studied using first-lactation 305-day mature equivalent (ME) milk and fat records of Holstein cows. Herds were divided into two categories, according to low or high herd-year phenotypic standard deviation for ME milk (HYSD). There were 330 sires with daughter records in both HYSD categories. Components of (co)variance, heritability, and genetic correlations for milk and fat yields were estimated using a sire model from bivariate analyses with a restricted maximum likelihood (REML) derivative-free algorithm. Sire and residual variances for milk yield in low HYSD herds were 79 and 57% of those obtained in high HYSD herd. For fat yield they were 67 and 60%, respectively. Heritabilities for milk and fat yields in low HYSD herds were larger (0.30 and 0.22) than in high HYSD herds (0.23 and 0.20). Genetic correlation between expression in low and high HYSD herds was 0.997 for milk yield and 0.985 for fat yield. Expected correlated response in low HYSD herds based on sires selected on half-sister information from high HYSD was 0.89 kg/kg for milk and 0.80 kg/kg for fat yield. Genetic evaluations in Brazil need to account for heterogeneity of variances to increase the accuracy of evaluations and the selection efficiency for milk and fat yields of Holstein cows. Selection response will be lower in low variance herds than in high variance herds because of reduced differences in daughter response and among breeding values of sires in low HYSD herds. Genetic investments in sire selection to improve production are more likely to be successful in high HYSD herds than in low HYSD Brazilian herds.

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Bibliographic Details
Main Author: COSTA, C. N.
Other Authors: CNPGL.
Format: Artigo de periódico biblioteca
Language:Ingles
English
Published: 1999-11-17
Subjects:Produção Leiteira, Gado Holandês,
Online Access:http://www.alice.cnptia.embrapa.br/alice/handle/doc/593700
https://doi.org/10.1590/S1415-47571999000300015
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spelling dig-alice-doc-5937002022-09-29T20:05:30Z An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments COSTA, C. N. CNPGL. Produção Leiteira Gado Holandês Heterogeneity of variance in Brazilian herd environments was studied using first-lactation 305-day mature equivalent (ME) milk and fat records of Holstein cows. Herds were divided into two categories, according to low or high herd-year phenotypic standard deviation for ME milk (HYSD). There were 330 sires with daughter records in both HYSD categories. Components of (co)variance, heritability, and genetic correlations for milk and fat yields were estimated using a sire model from bivariate analyses with a restricted maximum likelihood (REML) derivative-free algorithm. Sire and residual variances for milk yield in low HYSD herds were 79 and 57% of those obtained in high HYSD herd. For fat yield they were 67 and 60%, respectively. Heritabilities for milk and fat yields in low HYSD herds were larger (0.30 and 0.22) than in high HYSD herds (0.23 and 0.20). Genetic correlation between expression in low and high HYSD herds was 0.997 for milk yield and 0.985 for fat yield. Expected correlated response in low HYSD herds based on sires selected on half-sister information from high HYSD was 0.89 kg/kg for milk and 0.80 kg/kg for fat yield. Genetic evaluations in Brazil need to account for heterogeneity of variances to increase the accuracy of evaluations and the selection efficiency for milk and fat yields of Holstein cows. Selection response will be lower in low variance herds than in high variance herds because of reduced differences in daughter response and among breeding values of sires in low HYSD herds. Genetic investments in sire selection to improve production are more likely to be successful in high HYSD herds than in low HYSD Brazilian herds. 2022-09-29T20:05:21Z 2022-09-29T20:05:21Z 1999-11-17 1999 Artigo de periódico Genetics and Molecular Biology, v. 22, n. 3, p. 375-381, 1999. http://www.alice.cnptia.embrapa.br/alice/handle/doc/593700 https://doi.org/10.1590/S1415-47571999000300015 Ingles en openAccess
institution EMBRAPA
collection DSpace
country Brasil
countrycode BR
component Bibliográfico
access En linea
databasecode dig-alice
tag biblioteca
region America del Sur
libraryname Sistema de bibliotecas de EMBRAPA
language Ingles
English
topic Produção Leiteira
Gado Holandês
Produção Leiteira
Gado Holandês
spellingShingle Produção Leiteira
Gado Holandês
Produção Leiteira
Gado Holandês
COSTA, C. N.
An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments
description Heterogeneity of variance in Brazilian herd environments was studied using first-lactation 305-day mature equivalent (ME) milk and fat records of Holstein cows. Herds were divided into two categories, according to low or high herd-year phenotypic standard deviation for ME milk (HYSD). There were 330 sires with daughter records in both HYSD categories. Components of (co)variance, heritability, and genetic correlations for milk and fat yields were estimated using a sire model from bivariate analyses with a restricted maximum likelihood (REML) derivative-free algorithm. Sire and residual variances for milk yield in low HYSD herds were 79 and 57% of those obtained in high HYSD herd. For fat yield they were 67 and 60%, respectively. Heritabilities for milk and fat yields in low HYSD herds were larger (0.30 and 0.22) than in high HYSD herds (0.23 and 0.20). Genetic correlation between expression in low and high HYSD herds was 0.997 for milk yield and 0.985 for fat yield. Expected correlated response in low HYSD herds based on sires selected on half-sister information from high HYSD was 0.89 kg/kg for milk and 0.80 kg/kg for fat yield. Genetic evaluations in Brazil need to account for heterogeneity of variances to increase the accuracy of evaluations and the selection efficiency for milk and fat yields of Holstein cows. Selection response will be lower in low variance herds than in high variance herds because of reduced differences in daughter response and among breeding values of sires in low HYSD herds. Genetic investments in sire selection to improve production are more likely to be successful in high HYSD herds than in low HYSD Brazilian herds.
author2 CNPGL.
author_facet CNPGL.
COSTA, C. N.
format Artigo de periódico
topic_facet Produção Leiteira
Gado Holandês
author COSTA, C. N.
author_sort COSTA, C. N.
title An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments
title_short An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments
title_full An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments
title_fullStr An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments
title_full_unstemmed An investigation into heterogeneity of variance for milk and fat yields of hosteins cows in Brazilian herd environments
title_sort investigation into heterogeneity of variance for milk and fat yields of hosteins cows in brazilian herd environments
publishDate 1999-11-17
url http://www.alice.cnptia.embrapa.br/alice/handle/doc/593700
https://doi.org/10.1590/S1415-47571999000300015
work_keys_str_mv AT costacn aninvestigationintoheterogeneityofvarianceformilkandfatyieldsofhosteinscowsinbrazilianherdenvironments
AT costacn investigationintoheterogeneityofvarianceformilkandfatyieldsofhosteinscowsinbrazilianherdenvironments
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