Genetic parameters of milk, fat, and protein yields in the first three lactations, using an animal model and restricted maximum likelihood


Autoria(s): Albuquerque, L. G.; Keown, J. F.; VanVleck, L. D.
Contribuinte(s)

Universidade Estadual Paulista (UNESP)

Data(s)

20/05/2014

20/05/2014

01/03/1996

Resumo

Milk, fat, and protein yields of Holstein cows from the States of New York and California in the United States were used to estimate (co)variances among yields in the first three lactations, using an animal model and a derivative-free restricted maximum likelihood (REML) algorithm, and to verify if yields in different lactations are the same trait. The data were split in 20 samples, 10 from each state, with means of 5463 and 5543 cows per sample from California and New York. Mean heritability estimates for milk, fat, and protein yields for California data were, respectively, 0.34, 0.35, and 0.40 for first; 0.31, 0.33, and 0.39 for second; and 0.28, 0.31, and 0.37 for third lactations. For New York data, estimates were 0.35, 0.40, and 0.34 for first; 0.34, 0.44, and 0.38 for second; and 0.32, 0.43, and 0.38 for third lactations. Means of estimates of genetic correlations between first and second, first and third, and second and third lactations for California data were 0.86, 0.77, and 0.96 for milk; 0.89, 0.84, and 0.97 for fat; and 0.90, 0.84, and 0.97 for protein yields. Mean estimates for New York data were 0.87, 0.81, and 0.97 for milk; 0.91, 0.86, and 0.98 for fat; and 0.88, 0.82, and 0.98 for protein yields. Environmental correlations varied from 0.30 to 0.50 and were larger between second and third lactations. Phenotypic correlations were similar for both states and varied from 0.52 to 0.66 for milk, fat and protein yields. These estimates are consistent with previous estimates obtained with animal models. Yields in different lactations are not statistically the same trait but for selection programs such yields can be modelled as the same trait because of the high genetic correlations.

Formato

79-86

Identificador

http://www.gmb.org.br/Revistas/V19/v19a011.pdf

Brazilian Journal of Genetics. Ribeirao Pret: Soc Brasil Genetica, v. 19, n. 1, p. 79-86, 1996.

0100-8455

http://hdl.handle.net/11449/35575

WOS:A1996UF95400012

WOSA1996UF95400012.pdf

Idioma(s)

eng

Publicador

Soc Brasil Genetica

Relação

Brazilian Journal of Genetics

Direitos

openAccess

Tipo

info:eu-repo/semantics/article