• One reason for heightened interest in the milk of local breeds is a raft of research that implicates a protein — called A1 beta-casein and found in the milk of several European breeds — being linked to a risk of diabetes, ischemic disease and heart disease. Cattle that lack the A1 gene are categorised as A2.
• A1 and A2 beta-casein are genetic variants of the beta-casein milk protein that differ by a single amino acid.
• The A1 beta-casein type is the most common type found in cow’s milk in Europe (excluding France), the U.S., Australia and New Zealand.
• A controversial company, called the A2 Corporation (and now renamed the A2 Milk Company), patented and marketed a test that purportedly checked if a cow was likely to give A2 or A1-laced milk.
• While commercial breeds in India are dominantly A1, there are several indigenous breeds that may have the safer A2 genes that lead to milk free of A1 proteins.

Source: The Hindu