Genomic evaluation in commercial beef cattle population using real and simulated data

Abstract

This project aims to evaluate the impact on commercial beef cattle genetic evaluation by the inclusion of genomic information in the evaluation considering different uncertain paternity situations and different genotyping strategies in a real and simulated population. Will be simulated two herds, where one is a commercial beef cattle considering different proportion of genotyped young animals with unknown sire and maternal grandsire, and the second one will be a population belonging to a breeding program with complete pedigree and genomic information. The main idea is to use genomic information from young animals to quickly establishing genetic links between the commercial beef cattle population and a population from breeding program. The relationship matrix (A and G matrix) will be created considering different proportions of young animals (calves) with unknown sire (25, 50 and 75%) and unknown grandsires (0, 25, 50, 75 and 100%) to evaluate the implementation of BLUP and single step genomic BLUP (ssGBLUP). In this population, calves from the last three generations will be genotyped considering the proportion of 25, 50, 75 and 100% of the animals. Will be simulated phenotypic records for two traits with low (0.12) and moderate heritability (0.34) similar to stayability and yearling weight, respectively. Also, will be used real data with records for stayability and weight yearling traits from a Nelore cattle population provided by Nelore Brazil breeding program from National Association of Breeders and Researchers (ANCP). The database available contain genomic information of 11,000 animals and 30,000 and 60,000 phenotypic records for stayability and weight yearling, respectively. These information are from 18 farms located in the Southeast, Midwest and North of Brazil. The results of this project will allow: 1) To assess the impact of the use of genomic information in commercial beef cattle herds with different population structure; 2) Check the proportion of young genotyped animals necessary to obtain reliable genetic evaluations in commercial beef cattle herds; 3) evaluate the technical and economic feasibility of genomic evaluations using the ssGBLUP in commercial beef cattle herds; 4) To form and consolidate a research group at national and international level, consisting of different experts of recognized trajectory, this group will form a solid platform for the consolidation of future research projects; 5) Implement statistical methodologies for the use of genomic data in animal breeding. The information generated in this project will be widely disseminated at regional, national and international levels, through different strategies (presentations at national and international conferences, technical and scientific articles, abstracts, etc.), taking into account the different audiences (students, technicians, designers). In this process several actors of the beef industry will participate, from the farmers, researchers, technicians, graduate students, insemination centrals and industry. This project will outline strategies and tools that will support the genetic improvement of beef cattle commercial herds for several traits that influence the profitability of beef cattle systems. In addition, the results of this project should help to design strategies using genomic information that will identify genetically superior animals with higher reliably in commercial herds. (AU)