Resumo

GUILLEN TRUJILLO, Ariel et al. Parameters and genetic trends for weight at weaning and 18 months of age in red Zebu cattle in Cuba. Rev. mex. de cienc. pecuarias [online]. 2012, vol.3, n.1, pp.19-31. ISSN 2448-6698.

The objective was to estimate direct and maternal heritability of weaning weight at 7 mo of age (WW), and the final weight at 18 mo (FW) and breeding values and genetic trends for WW and FW in Zebu bermejo cattle of Cuba. A bi-character animal model was used in 5,120 records of WW and 1,134 of FW. The animals were born between 1982 and 2008 in three herds. The statistical model for WW included the effects of the group of contemporaries (herd-year-birth season-sex, age at weaning as linear co-variable and age of the mother as linear and quadratic covariable), random effect of the animal, random maternal effect, permanent environmental effect and the error. The model for FW included the group of contemporaries (herd-year-birth season) age at final weight as linear co-variable, random effect of the animal, permanent environmental effect and the error. Genetic tendencies were estimated by linear regression of the average additive genetic value on the birth years from 1982 to 2007. The heritability estimated for the WW were 0.11±0.04 and 0.03±0.02 (direct and maternal effects, respectively), with a genetic correlation of -0.15±0.24 between these effects. The heritability for the FW was 0.28±0.10. Genetic tendencies were positive and significant for direct effects of PD (0.102 kg) and PF (0.244 kg). It is concluded that the heritability of the direct and maternal effects of the WW were low and that the FW has a moderate heritability that can favor the response to selection in breeding programs.

Palavras-chave : Heritability; Cattle in the tropics; Breeding value; Final weight.

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