Marcos Eli Buzanskas;Daniela do Amaral Grossi;Ricardo Vieira Ventura;F.S. Schenkel;T.C.S. Chud;Nedenia Bonvino Stafuzza;Luciana Diniz Rola;Sarah Laguna Conceição Meirelles;Fabiana Barichello Mokry;Maurício de Alvarenga Mudadu;R. H. Higa;Marcos Vinícius Gualberto Barbosa da Silva;M. M. de Alencar;Luciana Correia de Almeida Regitano;Danísio Prado Munar

Embrapa Agricultural Informatics, Campinas, Brazil;Departamento de Zootecnia, Universidade Federal da Paraíba (UFPB), Areia, Brazil;Department of Animal Science, Federal University of Lavras (UFLA), Lavras, Brazil;Departamento de Ciências Exatas, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, Brazi;Department of Genetics and Evolution, Federal University of São Carlos (UFSCar), São Carlos, Brazil;Embrapa Southeast Livestock, São Carlos, Brazil;Department of Animal and Poultry Science, University of Guelph, Centre for Genetic Improvement of Livestock (CGIL), Guelph, Canada;Beef Improvement Opportunities (BIO), Guelph, Canada;Departamento de Ciências Exatas, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, Brazil;Departamento de Zootecnia, Núcleo de Pesquisa e Conservação de Cervídeos, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, Brazil;Fast Genetics, Saskatoon, Canada;Embrapa Dairy Cattle, Juiz de Fora, Brazil

Animal breeding;Composite breed;Genome-wide association;Genomic data;Single nucleotide polymorphis

Background: Beef cattle breeding programs in Brazil have placed greater emphasis on the genomic study of reproductive traits of males and females due to their economic importance. In this study, genome-wide associations were assessed for scrotal circumference at 210 d of age, scrotal circumference at 420 d of age, age at first calving, and age at second calving, in Canchim beef cattle. Data quality control was conducted resulting in 672,778 SNPs and 392 animals. Results: Associated SNPs were observed for scrotal circumference at 420 d of age (435 SNPs), followed by scrotal circumference at 210 d of age (12 SNPs), age at first calving (six SNPs), and age at second calving (four SNPs). We investigated whether significant SNPs were within genic or surrounding regions. Biological processes of genes were associated with immune system, multicellular organismal process, response to stimulus, apoptotic process, cellular component organization or biogenesis, biological adhesion, and reproduction. Conclusions: Few associations were observed for scrotal circumference at 210 d of age, age at first calving, and age at second calving, reinforcing their polygenic inheritance and the complexity of understanding the genetic architecture of reproductive traits. Finding many associations for scrotal circumference at 420 d of age in various regions of the Canchim genome also reveals the difficulty of targeting specific candidate genes that could act on fertility; nonetheless, the high linkage disequilibrium between loci herein estimated could aid to overcome this issue. Therefore, all relevant information about genomic regions influencing reproductive traits may contribute to target candidate genes for further investigation of causal mutations and aid in future genomic studies in Canchim cattle to improve the breeding program.