Genomic prediction and genome-wide association analysis of female longevity in a composite beef cattle breed.

Longevity is a highly important trait to the efficiency of beef cattle production. The objective of this study was to evaluate the genomic prediction of longevity and identify genomic regions associated with this trait. The data used in this study consisted of 547 Composite Gene Combination cows (1/2 Red Angus, 1/4 Charolais, 1/4 Tarentaise) born from 2002 to 2011 genotyped with Illumina BovineSNP50 BeadChip. Three models were used to assess genomic prediction: Bayes A, Bayes B and GBLUP using a genomic relationship matrix. To identify genomic regions associated with longevity 2 approaches were adopted: single marker genome wide association and Bayesian approach using GenSel software. The genomic prediction accuracy was low 0.28, 0.25, and 0.22 for Bayes A, Bayes B and GBLUP, respectively. The single-marker genome wide association study (GWAS)identified 5 loci with -value less than 0.05 after false discovery correction: UA-IFASA-7571 on chromosome 19 (58.03 Mb), ARS-BFGL-BAC-15059 on BTA 1 (28.8 Mb), ARS-BFGL-NGS-104159 on BTA3 (29.4 Mb), ARS-BFGL-NGS-32882 on BTA9 (104.07 Mb) and ARS-BFGL-NGS-32883 on BTA25 (33.77 Mb). The Bayesian GWAS yielded 4 genomic regions overlapping with the single marker GWAS results. The region with the highest percentage of genomic variance (3.73%) was detected on chromosome 19. Both GWAS approaches adopted in this study showed evidence for association with various chromosomal locations.