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Arquivo Brasileiro de Medicina Veterinária e Zootecnia

Print version ISSN 0102-0935

Abstract

SILVA, N.A.M. et al. Proposal for genetic analysis of growth curves of cattle through the SAEM algorithm. Arq. Bras. Med. Vet. Zootec. [online]. 2012, vol.64, n.5, pp. 1256-1264. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352012000500025.

Two methodologies in genetic evaluation of growth curves of Nellore cattle were compared: the SAEM algorithm and the Two Step method. To implement these methodologies the Brody modified growth curve and the sire model were used. The difference between the SAEM and the Two Step is that SAEM estimates jointly the parameters of the model and genetics and environmental effects and the Two Step method does this process in two independent steps. Estimates of the fixed effects and genetics parameters, and prediction breeding values for the sires were obtained from the methodologies. From the breeding values genetic curves were obtained for the sires. The SAEM algorithm proved consistent in the estimation of fixed effects and prediction of random effects.

Keywords : (co)variance components; stochastic algorithm EM; genetics curves.

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