Short communication: Principal components and factor analytic models for test-day milk yield in Brazilian Holstein cattle


Autoria(s): Bignardi, A. B.; El Faro, L.; Rosa, G. J. M.; Cardoso, V. L.; Machado, P. F.; Albuquerque, Lucia Galvão de
Contribuinte(s)

Universidade Estadual Paulista (UNESP)

Data(s)

20/05/2014

20/05/2014

01/04/2012

Resumo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A total of 46,089 individual monthly test-day (TD) milk yields (10 test-days), from 7,331 complete first lactations of Holstein cattle were analyzed. A standard multivariate analysis (MV), reduced rank analyses fitting the first 2, 3, and 4 genetic principal components (PC2, PC3, PC4), and analyses that fitted a factor analytic structure considering 2, 3, and 4 factors (FAS2, FAS3, FAS4), were carried out. The models included the random animal genetic effect and fixed effects of the contemporary groups (herd-year-month of test-day), age of cow (linear and quadratic effects), and days in milk (linear effect). The residual covariance matrix was assumed to have full rank. Moreover, 2 random regression models were applied. Variance components were estimated by restricted maximum likelihood method. The heritability estimates ranged from 0.11 to 0.24. The genetic correlation estimates between TD obtained with the PC2 model were higher than those obtained with the MV model, especially on adjacent test-days at the end of lactation close to unity. The results indicate that for the data considered in this study, only 2 principal components are required to summarize the bulk of genetic variation among the 10 traits.

Formato

2157-2164

Identificador

http://dx.doi.org/10.3168/jds.2011-4494

Journal of Dairy Science. New York: Elsevier B.V., v. 95, n. 4, p. 2157-2164, 2012.

0022-0302

http://hdl.handle.net/11449/4485

10.3168/jds.2011-4494

WOS:000301885700054

Idioma(s)

eng

Publicador

Elsevier B.V.

Relação

Journal of Dairy Science

Direitos

closedAccess

Palavras-Chave #factor analytic model #Multivariate analysis #Reduced rank model
Tipo

info:eu-repo/semantics/article