Genetic evaluation of temperament trait by visual score in Nellore cattle / Avaliação genética da característica de temperamento por escore visual em bovinos Nelore

ABSTRACT

The national herd is predominantly composed by Nelore breed (Bos indicus), being extremely important for beef cattle, even though, it have limitations as aggressive temperament compared to populations of Bos taurus origin. The temperament (TEMP) can be defined as the perception and reaction of the animals when they feel fear or are managed by man. More reactive cattle have lower weight gain, produce beef of lower quality, are more susceptible to diseases and have low reproductive performance. The objective of this research was to obtain the components of (co) variances and genetic parameters of TEMP in order to provide subsidies to farmers and technicians on its use in animal breeding programs. For the TEMP trait, the database used was from the Nelore breeding program Nelore Qualitas. Data was recorded from 2000 to 2009, on 20 farms across six Brazilian states, on 48,879 males and females ranging in age from 450 to 599 days. TEMP trait was performed by visual scores, in 1-5 scale, where higher scores means less reactive animals. The genetic parameters were estimated with univariate animal model and Bayesian inference, using the program GIBBS2F90. The statistical model included fixed effects of contemporary group, age at measurement as a linear covariate, and random effects of additive genetic and residual. The data set included 455 sires, 28,111 dams and 3,153 contemporary gr

RESUMO

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