title: Genetic parameter estimation for pre- and post-weaning traits in Brahman cattle in Brazil.
abstract: 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.
authors.affiliation: Departamento de Ciências Exatas, Faculdade de Ciências Agrárias e Veterinárias (FCAV), UNESP-Univ Estadual Paulista, Via de Acesso Professor Paulo Donato Castellane, Jaboticabal, São Paulo, 14884-900, Brazil.
authors.forename: Giovana
authors.initials: G
authors.lastname: Vargas
authors.forename: Marcos Eli
authors.initials: ME
authors.lastname: Buzanskas
authors.forename: Diego Gomes Freire
authors.initials: DG
authors.lastname: Guidolin
authors.forename: Daniela do Amaral
authors.initials: Ddo A
authors.lastname: Grossi
authors.forename: Alexandre da Silva
authors.initials: Ada S
authors.lastname: Bonifácio
authors.forename: Raysildo Barbosa
authors.initials: RB
authors.lastname: Lôbo
authors.forename: Ricardo
authors.initials: R
authors.lastname: da Fonseca
authors.forename: João Ademir de
authors.initials: JA
authors.lastname: Oliveira
authors.forename: Danísio Prado
authors.initials: DP
authors.lastname: Munari
mesh_terms: D000367:Age Factors; D000818:Animals; D001835:Body Weight / Q000235:genetics* / Q000502:physiology; D001938:Brazil; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000235:genetics* / Q000254:growth & development*; D016013:Likelihood Functions; D016014:Linear Models; D008957:Models, Genetic; D020412:Multifactorial Inheritance / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D014886:Weaning