Genomic tools to genetic improvement of direct economic important traits in Nelore cattle

Abstract

Beef cattle production is an important socioeconomic activity for Brazil and the World. To date, in the world meat market, there is a tendency to value differentiated meat products (i.e., value added-products), in terms of meat organoleptic traits and consequences of meat consumption on human health. Also, there is a growing concern about the impact of livestock production systems on the environment and the competition between humans and livestock species for the same sources of food like grains and supplements. In this world scenario, in order to increase profitability of beef cattle production maintaining sustainability, traits associated to carcass and meat quality, as well as to feed conversion would be relevant. Until now, meat and carcass traits and those associated with feed conversion have not been considered in beef cattle breeding programs, probably because of the high costs and difficulties for recording these traits. Recently, there are some Brazilian research institutions that have collected records for these traits, mainly carcass and meat traits. However, studies in the genetic quantitative area reporting genetic parameter estimates for these traits are rare. Moreover, in general, the samples are small since is not to easy obtain these traits under field conditions (no experimental data). Thus, before including traits associated to carcass and meat quality, as well as feed conversion, in beef cattle breeding programs, it is necessary to have genetic parameter estimates for these traits obtained from various different samples. Important advances in molecular genetic techniques, as the high density SNP panel, will allow significant genetic gains, mainly, for traits that are costly and difficulty to measure, as is the case of carcass, meat and feed conversion traits. However, methodologies that allow to the inclusion of genomic data in Brazilian beef cattle genetic evaluation are still necessary. The objectives of this project are to build a dataset with carcass, meat and feed conversion traits, as well as to use data from others economic important traits that are normally recorded in beef cattle breeding programs, as growth and reproductive traits; to search for DNA polymorphisms associated to these traits; and to develop methodologies and software to apply genomic selection. To achieve these objectives the following topics will be developed in the project: a) Quantitative genetic analyses of carcass, meat and feed conversion traits and their associations with others traits of economic importance; b) Association studies between single nucleotide polymorphisms (SNP) and economic important traits in Nelore cattle; c) Expression studies of genes associated to carcass, meat and feed conversion traits; d) Development and implementation of an algorithm to simulate molecular data to perform genetic evaluation using SNP´s; f) Genomic selection for carcass, meat and feed conversion traits in Nelore cattle. (AU)