Selection of a suitable data set and model for the estimation of genetic parameters of the weaning weight in beef cattle
Abstract. The objective of this paper was to select a suitable data subset and statistical model for the estimation of genetic parameters for weaning weight of beef cattle in the Czech Republic. Nine subsets were tested for the selection of a suitable subset. The subsets differed from each other in the limit of sampling criteria. The most suitable subset satisfied these conditions: at least 5 individuals per each sire, 5 individuals per HYS (herd, year, season), 2 sires per HYS, and individuals per dams that have at least one half-sister and two offspring (n = 4 806). The selection of a suitable model was carried out from 10 models. These models comprised some of the random effects: direct genetic effect, maternal genetic effect, permanent maternal environment effect, HYS, sire × herd or sire × year interaction, and some of the fixed effects: dam’s age, sex (young bull, heifer × single, twin born), HYS, year, herd. The direct heritability (h2a) ranged from 0.06 to 0.17, of maternal heritability (h2m) from 0.03 to 0.06. The genetic correlations between the direct and maternal effect (ram) were in the range of –0.15 –0.42.
