The disclosure relates to the use of genetic traits in livestock for determining breeding characteristics of livestock progeny, and for optimizing the management and marketing of livestock for improving feedlot performance and meat quality. The disclosure specifically relates to genetic markers and single nucleotide polymorphisms (SNPs) in the bovine somatostatin locus, as well as haplotypes that include the somatostatin locus, which are associated with certain quantitative trait loci (QTLs), such as marbling, meat quality grade, and yield grade. In a preferred embodiment, the SNPs and haplotypes are predictive of the increased or decreased amount of tissue marbling in the animal.