Comparison of models for genetic analysis of traits from performance test of gilts using restricted maximum likelihood

The objectives of this research was to compare estimates of variance components using different animal models in order to determine whether simpler models produce estimates similar to those produced by more complex alternatives, and to determine the most suitable mixed model for estimating genetic parameters and genetic trends for traits in performance test of gilts using REML. Four mixed model was constructed: M1 (Random effect of Animal and fixed effects of farm, year, season and breed), M1 (M1 + regression influence of body weight at the end of performance test), M3 (M1 + regression influence of duration of performance test), and M4 (M2 + regression influence of body weight at the end of performance test). In examined mixed models, information criteria was lowest in model M4, which would be the most adequate model, while model M1 had largest information criteria, which suggested that this model was not suitable model for evaluation of genetic parameters. Strong negative genetic and phenotypic correlation is showed between MP and BFT1 and between MP and BFT2, while between AG and BFT1 and BFT2 established positive and negative genetic and phenotypic correlation. Between BFT1 and BFT2 was determined strong positive genetics and phenotypic correlation. Heritability traits in four models were at medium to high degree of heritability. The resulting genetic trends were different between models, with relatively high coefficients of determination (R2).