Exploring the use of genomic information in multi-character norm of reaction models to assess genotype-environment interaction in traits indicative of sexual precocity in Nelore cattle.

• Grant number: 24/04673-4
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): October 01, 2024
• Effective date (End): July 31, 2026
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Fernando Sebastián Baldi Rey
• Grantee: Eduarda da Silva Oliveira
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The evaluation of reproductive traits has played a crucial role in the genetic improvement of cattle. These traits are strongly influenced by genetic, environmental factors, and the combination of these factors leading to different adaptive responses to a variety of factors, including climatic conditions, nutritional conditions, management practices, and resource availability. In view of this, this project aims to analyze the interaction between genotype and environment (GxE) in traits indicative of sexual precocity in Nelore cattle. Additionally, it aims to investigate the genetic relationships between these traits in different environments using multi-character norm of reaction models. The traits to be evaluated as indicators of sexual precocity in heifers will be age at first calving (AFC), probability of early calving (PEC30), and in young bulls will be scrotal circumference at 365 days (SC365) and age at male puberty (AMP), with approximately 414,000, 200,000, 500,000, and 25,000 phenotypic observations, respectively. The data used to evaluate the GxE interaction will be provided by the National Association of Breeders and Researchers (ANCP). The assessment of the GxE interaction will be performed using a multi-character norm of reaction model via single-step genomic regression (ssGRN). In the first step, the animal model will be used to estimate the environmental gradient (EG) based on weight at 365 days, and in the second step, the multi-character ssGRN model will be used to assess the GxE interaction. GWAS analyses will be conducted for both intercept and slope effects. This project aims to understand how the environment influences the expression of traits indicative of sexual precocity and evaluate its impact on the genetic potential of animals, which may provide significant contributions to producers in different regions of Brazil.