The present invention provides for selection of
livestock animals, including bovines, whose genotypes based in the STAT6
gene are correlated with phenotypes reflecting desirable carcass and
feedlot traits. These phenotypes include
back fat (BFAT), calculated yield grade (CALCYG), cutability (
CUT), hot
carcass weight (HCW),
dry matter intake (DMI), days on feed (DOF),
back fat rate (BFAT RATE) and average daily
gain (ADG), based on the knowledge of the STAT6 genotypes. The
predictive value is based in part on the discovery that certain single
nucleotide polymorphisms (SNPs) within the STAT6
gene are linked to phenotypes of economically these important carcass and
feedlot traits. Also provided are SNPs within the STAT6
gene useful in reliably distinguishing between a Bos taurus and a Bos indicus bovine. The invention provides methods and compositions for determining STAT6 genotypes and for screening
livestock animals to predict which animals will have desirable carcass traits and
feedlot traits, allowing producers to selectively
breed and manage animals based on desired characteristics, thereby maximizing productivity and profitability in commercial meat production operations.