A highly sensitive PCR method for A1 allele detection in A2 milk samples without DNA isolation.

We previously developed a genotyping method to detect the A1 and A2 alleles of the bovine β-casein gene. This method required DNA extraction from hair samples. Recently, demand for A2 milk (milk from cows homozygous for the A2 allele) has increased, and dairy farms are required to have certification to produce A2 milk.