Spatial distribution of genetic values of Nelore breed in Brazil

Abstract

This aim of this study was to analyze the influence of socieoconomic, environmental and farm variables on the existing genetic values (Expected Progeny Differences - EPDs) of the different clusters of Nelore animals in Brazil. The data evaluated included EPDs of 1,462,485 animals, males and females born between 2000 to 2011, same period of the compiled variables used (socieoconomic, environmental and farm), distributed in 171 municipality from 15 Brazilian states by GENEPLUS (Genotype Breeding Program of Embrapa Beef Cattle). The municipality averages of sixteen variables were used for weight traits (maternal and direct genetic effects for weight at 120 days, maternal and direct genetic effects at birth and weaning weight, post-yearling weight and average daily gain post-weaning), carcass quality (carcass conformation at weaning, carcass conformation at post-yearling, eye muscle area, subcutaneous fat thickness and marbling) and reproductive traits (scrotal perimeter at weaning, scrotal perimeter at post-yearling, age at first calving and cow weight at weaning) as well as their respective accuracies. The data were spatialized in the ArcGIS program along with environmental factors and human development indicators. The statistics included clustering, discriminant and canonical analyzes using the SAS® program. Three clusters for weight traits, five for carcass quality, four for reproductive traits and five for accuracy were formed. The clusters showed good distribution across the country, highlighting the clusters with highest genetic values for each trait type. Discrimination was seen among environments for beef cattle at pasture, depending on climatic conditions. The spatial distribution of the Nelore cattle breed may provide a better understanding of the real situation of the breed in different Brazilian climates and environments. The results of this study can be used to correct possible errors of genetic selection programs that use the same breeders and females for different environments.