THe foods we eat have far reaching consequences IMO-- and for me I don't drink milk anymore at all because the sugar count is very high. CHeese is a whole nother matter. If I am understanding the A1-A2 concept correctly, it maybe time to ditch the sheep of 25 years, and bring in goats. Food for thought. lol
All sheep are homozygous A2.
That documentation, along with component testing for all the various dairy breeds can be found at the various research websites in several countries and here in the US at both the Spooner research station and the National database.
Most Holsteins are not, very few jerseys are, some Dexters are (which is what I have), and most Guernsey are.