There is a good explanation of A1A2 status at the company website a2milkcompany.com (they have a US site)Basically about 3000 years ago there was a genetic mutation in dairy cattle that they started producing A1 proteins and A2 proteins. A2 is the natural original. More studies have shown the A1 protein is what causes the gastro distress. It’s a New Zealand company but has US headquarters in Boulder. They have 3 processing plants in the US and their milk is easy to spot A2 on the carton. They have a huge infant formula market selling to mostly China. Lots of info out there. It’s just delicious natural milk and the farmers in the US that have converted their herd get a premium price for their milk.