Correlação genética entre idade ao primeiro parto e característica de crescimento de fêmeas da raça canchim.

Abstract

The objective of this study was to estimate genetic correlations between age at first calving (AFC) and parameters A (asymptotic weight) and k (maturation rate) of Von Bertalanffy’s model and mature weight (MW) of females of the Canchim beef cattle breed. (Co)variance components were estimated by the restricted maximum likelihood method, in two-trait analyses of AFC with A, k and MW, using an animal model with additive direct and residual random effects and the fixed effects of year and season of birth for AFC, A and k, and year and season of calving for MW. The heritability estimates were 0.27 (A), 0.37 (k), 0.48 (MW) and 0.03 (FAC). The genetic correlations between AFC and A (0.16), k (-0.75) and MW (0.25) show that selection for higher maturation rate and small asymptotic weight would decrease AFC and, then, improve productivity of Canchim herds.