Genetic associations between flight speed and growth traits in Nellore cattle

• Grant number: 12/18451-6
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: October 01, 2012
• End date: March 31, 2013
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Mateus José Rodrigues Paranhos da Costa
• Grantee: Mateus José Rodrigues Paranhos da Costa
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The aim of the present study was to estimate genetic parameters for flight speed and its association with growth traits in Nellore beef cattle. The flight speed (FS) of 7,402 yearling animals was measured using a device composed of a pair of photoelectric cells. Time interval data (s) were converted to speed (m/s), and faster animals were regarded as more reactive. The growth traits analyzed were weaning weight (WW), average daily weight gain from weaning to yearling age (ADG) and yearling scrotal circumference (SC). The (co)variance components were estimated by REML in a multi-trait analysis applying an animal model. The model included the random direct additive genetic and residual effects, the fixed effects of contemporary groups (CG) and of age of the dam (classes) and age of the animal as covariable. For WW, the model also included the maternal genetic and permanent environmental random effects. Direct heritability estimate for FS was 0.26 ± 0.05 and for WW, SC and ADG, were 0.30 ± 0.01, 0.48 ± 0.02 and 0.19 ± 0.01, respectively. Estimates of the genetic correlation between FS and the growth traits were -0.12 ± 0.07 (WW), -0.13 ± 0.08 (ADG) and -0.11 ± 0.07 (SC). Though the low values, these correlations showed that animals with better temperaments (slower FS) tended to present better performance. It is possible to infer that long term selection for weight and scrotal circumference can promote a positive genetic response in animals' temperament. Nevertheless, to obtain faster genetic progress in temperament, it would be necessary to perform direct selection for such trait. Flight speed is an easily measured indicator of temperament and can be included as a selection criterion in breeding programs for Nellore cattle. (AU)