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Reaction norm models for study genotype x environment interaction in Nellore cattle

Grant number: 16/17517-4
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): December 01, 2016
Field of knowledge:Agronomical Sciences - Animal Husbandry
Principal Investigator:Claudia Cristina Paro de Paz
Grantee:Anielly de Paula Freitas
Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Associated scholarship(s):19/01814-8 - Reaction norm models for study genotype by environment interaction in Nellore cattle, BE.EP.DR


The phenotype is controlled by genetic inheritance, by environment and by the interaction of these factors. Most of the traits economic interest are polygenic, that is, are under influence of a large number of genes. The action of these genes may be conditioned by the set of environmental effects, thus is very important to study the genotype x environment effect on growth traits in Nellore cattle. The aim of this study will be to evaluate the importance of genotype x environment interaction and the effect of different selection practices for weight at 210 days of age for males and females, weight at 378 days for males and weight at 550 days for females on the environmental sensitivity of Nellore cattle from three herds, through the study of reaction norms to the environment, obtained by random regression using Bayesian approach, and estimate the genetic trend of the herds. Will be used approximately 8482 information of the animals Nellore, born between the years 1981 and 2015, from three herds of the Centro APTA Bovinos de Corte, of Instituto de Zootecnia of Sertãozinho, SP. The components (co)variance and genetic parameters will be estimated for the three traits, in the three herds, using a standard animal model (AM) and two hierarchical models of reaction norms (homogeneous and heterogeneous residue). To check the best model will be used the deviance information criterion (DIC). Genetic trends will be estimated for each herd and trait both for the general level of production (intercept of RN) as to the specific ability to response to environmental variations (slope of RN).