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BIBTEX RIS

Random regression models using different functions to model test-day milk yield of Brazilian Holstein cows

2011; Research Foundation of Ribeirão Preto; Volume: 10; Issue: 4 Linguagem: Inglês

10.4238/2011.october.31.4

ISSN

1676-5680

Autores

Annaíza Braga Bignardi, Lenira El Faro, R.A.A. Torres Júnior, V.L. Cardoso, Paulo Fernando Machado, Lúcia Galvão de Albuquerque,

Tópico(s)

Genetics and Plant Breeding

Resumo

We analyzed 152,145 test-day records from 7317 first lactations of Holstein cows recorded from 1995 to 2003.Our objective was to model variations in test-day milk yield during the first lactation of Holstein cows by random regression model (RRM), using various functions in order to obtain adequate and parsimonious models for the estimation of genetic parameters.Test-day milk yields were grouped into weekly classes of days in milk, ranging from 1 to 44 weeks.The contemporary groups were defined as herd-test-day.The analyses were performed using a single-trait RRM, including the direct additive, permanent environmental and residual random effects.In addition,

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