Abstract

Von Bertalanffy nonlinear model was used to fit weight-age data for 575 females Guzera (Zebu beef cattle) 
reared under range conditions in southeastern Brazil, to obtain estimates of h2 and genetic and phenotypic 
correlation for the relevant growth curve parameters, weights from 240 to 730 days of age and reproductive 
traits. The (co)variance components were obtained by REML fitting univariate and bivariate animal models. 
The h2 estimates in univariate analyses for growth curve parameters A and k were 0.63 and 0.08 respectively, 
and agreed closely with those of the various bivariate analyses. Genetic and phenotypic correlation between A 
and k were high and negative. Genetic correlations between observed weights and A and k indicated that 
selection for weight will reduce maturation rate and improve mature weight, although, phenotypically, heavier 
animals on ages considered were also early maturing. Correlations among parameters A and k and reproductive 
traits indicated that heavier and late maturing cows were also sexually late maturing.
 

Henrique N Oliveira, Raysildo B Lôbo, C. S Pereira

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 19. Selection and quantitative genetics; growth; reproduction; lactation; fish; fiber; meat., , 189–192, 1994