Comparison between some selection criteria for growth traits correlated to scrotal circumference

Data to 53433 of Nellore cattle were used to estimate genetic parameters for standardized weights at 120, 240, and 550 days of age (P120, P240, and P550 respectively), scrotal circumference at 550 days (PE550), days to reach 160 kg (13160), and 240 kg (D240) of live weigh. It was used software the MTDFREML with mixed-model analysis using animal model. Model included fixed effects of contemporary groups (GC) and classes of age-of-dam calving and random direct and maternal genetic effects, the dam permanent environmental effect and the error. Direct heritability (h(2)a), in multiple-trait analysis between PE550 and all others traits, were .19 (for PI 20 and P240). .34 (for P550), .09 (for D160), .16 (for D240) and .36 (mean for PE550). Maternal heritability for growth traits ranged from .02 to .12. Genetic correlations among PE550 and the others traits had medium magnitude. Standardized weights rather than days to live weight, were better selection criteria when heritabilities and selection response were consideraded.