| Author(s): |
Vargas, Giovana
[1]
;
Buzanskas, Marcos Eli
[1]
;
Freire Guidolin, Diego Gomes
[1]
;
Grossi, Daniela do Amaral
[2]
;
Bonifacio, Alexandre da Silva
[3]
;
Lobo, Raysildo Barbosa
[3]
;
da Fonseca, Ricardo
[4]
;
de Oliveira, Joao Ademir
[1]
;
Munari, Danisio Prado
[1]
Total Authors: 9
|
| Affiliation: | [1] Univ Estadual Paulista, FCAV, Dept Ciencias Exatas, BR-14884900 Sao Paulo - Brazil
[2] Univ Guelph, Dept Anim & Poultry Sci, CGIL, Guelph, ON N1G 2W1 - Canada
[3] ANCP, BR-14020230 Sao Paulo - Brazil
[4] Univ Estadual Paulista, Fac Zootecnia, Unidade Diferenciada Dracena, BR-17900000 Sao Paulo - Brazil
Total Affiliations: 4
|
Beef cattle producers in Brazil use body weight traits as breeding program selection criteria due to their great economic importance. The objectives of this study were to evaluate different animal models, estimate genetic parameters, and define the most fitting model for Brahman cattle body weight standardized at 120 (BW120), 210 (BW210), 365 (BW365), 450 (BW450), and 550 (BW550) days of age. To estimate genetic parameters, single-, two-, and multi-trait analyses were performed using the animal model. The likelihood ratio test was verified between all models. For BW120 and BW210, additive direct genetic, maternal genetic, maternal permanent environment, and residual effects were considered, while for BW365 and BW450, additive direct genetic, maternal genetic, and residual effects were considered. Finally, for BW550, additive direct genetic and residual effects were considered. Estimates of direct heritability for BW120 were similar in all analyses; however, for the other traits, multi-trait analysis resulted in higher estimates. The maternal heritability and proportion of maternal permanent environmental variance to total variance were minimal in multi-trait analyses. Genetic, environmental, and phenotypic correlations were of high magnitude between all traits. Multi-trait analyses would aid in the parameter estimation for body weight at older ages because they are usually affected by a lower number of animals with phenotypic information due to culling and mortality. (AU) |