Genetic, phenotypic and environmental parameters for behavioral characteristics of Nellore cattle

The research for good welfare conditions is a tendency in animal production because it is already proved that the efficiency of animal protein production systems is related to animal behavior. The aim of this study was to estimate genetic parameters of temperament score and exit time (variables of animal behavior) and weight, body condition score and rump height of Nelore bulls. Data from 905 Nelore cattle, males and females (older than 250 days) from Instituto de Zootecnia in Sert?ozinho herd beef cattle were collected totalizing 1872 measurements between the years 2014 and 2015. The analyses were performed using linear models containing the fixed effects of selection row, sex of the animal, year of birth year of assessment and handling corral and the age of the animal as a covariate (linear and quadratic). The (co)variance components were estimated by Bayesian statistical inference using the THRGIBBS1F90 program, using an multi-trait animal model, including, as random the direct additive effects, direct permanent environment and residual. The heritability estimates for temperament score, exit time, body condition score, body weight and rump height for Nellore animals were 0.08; 0.14; 0.54; 0.46 and 0.93, respectively. The genetic correlation between the animal behavior variables was high and negative (-0.80), which means that animals with lower temperament scores (calmest individuals) will take longer to go 1.5m. The exit time was the variable with more favorable correlation with body weight body condition score and rump height (0.27; 0.56 and 0.37 respectively), which suggest that animals take more time to exit will be better in body weight, body condition score and rump height. The use of the behavioral characteristics cited in this study could result in a genetic gain if are included in a breeding program.