Marker-assisted selection of dairy cows for β-casein gene A2 variant

Many studies highlighted potential associations of β-casein A1 with specific human diseases and a minor digestibility of milk, due to the bioactive peptide β-casomorphin 7 (BCM-7) release during digestion. Conversely, the ancestral β-casein A2 variant seems to be a favorable trait because it is not associated with BMC-7 release. The aim of this work was to evaluate frequencies of β-casein variants in offspring of previously genotyped cows inseminated with A2 homozygous semen. The frequency of the A2/A2 animals has almost doubled from 37 to 69%. These are encouraging results with the perspective of reaching the goal of producing A2 milk