What’s Up with A2 Milk?


By Leigh Glenn

“A2” and “A1” refer to the types of beta-casein found in milk, with older African and Asian breeds predominating in A2 milk. A1 derives from a mutation that occurred 5,000 to 10,000 years ago. Most European breeds of cows are believed to have the mutation.

Human studies have been controversial. Did your bloating come from A1 milk or something else you ate? A1 milk reportedly is the milk that is behind digestive difficulties and potentially other ill effects. Researchers are continuing to investigate this.

For those in the dairy business, A2 milk could create concerns or huge opportunities. Clearly, to change an A1 herd over to an A2 herd takes an investment in capital and time. It could take between 4-12 years and several generations of cows, depending on the extent to which the A2 gene is already present in the herd. Some older breeds, such as Jerseys, perhaps half the herd is A2; with others, like Guernseys, it’s thought to be above 90 percent of the herd. Converting a herd means getting semen from A2/A2 bulls and to keep breeding until the herd is completely A2.

Dairy farmer Mary Fendrick of Woodbourne Creamery, Mt. Airy, MD., thinks it may be anecdotal that people who have issues digesting lactose seem more intolerant to A1 than A2, but she is benefiting from the search for A2 milk. Some of Woodbourne’s customers come from as far as Richmond, VA in search of the creamery’s mostly A2 milk. She estimates their herd to be about 85 to 90 percent A2 dairy cows and says the one consistent trait they look for in sire semen is that it is from A2/A2 bulls.

Leigh Glenn is a contributor to Edible DC and is a freelance writer and editor based in Annapolis, MD. She writes about farming, food, permaculture, gardening, herbalism and enjoys cooking—and hooking, with wool to create fiber paintings.