Tag: Holstein cows

The majority of commercially available dairy milk in countries like the United States, Australia, and much of Europe contains both A1 and A2 beta-casein proteins. This mix is largely due to the widespread use of certain cow breeds, leaving many to wonder, "Which cow's milk is A1?" The answer lies in the genetic makeup of the dairy cattle itself.

Genetic analysis indicates that many modern dairy breeds, particularly those of Northern European origin, produce milk containing the A1 beta-casein protein. An example of A1 milk is the standard cow's milk from common breeds like Holstein-Friesian and Ayrshire. This article explores the origins of A1 milk, the breeds that produce it, and its distinction from A2 milk.

Genetic research shows that most Holstein cow herds carry a mixture of both A1 and A2 beta-casein protein genes. This means the milk typically sold from these cattle is a blend of both A1 and A2 proteins, which some individuals may find harder to digest than pure A2 milk.