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Do you select for A2A2 bulls within your genetic plan? Find a link here to download an extensive list of our A2A2 qualified sires.
Cows’ milk is about 87 percent water and 13 percent solids. Those solids are a combination of lactose (milk sugar), fat, protein, and minerals. If you focus in on the protein within milk, the major component of that milk protein is called casein.
One type of casein within milk is beta casein. There are two different beta casein genes that cattle can have - A1 or A2. These two types of beta casein are found at two different locations, so any given bovine will be either A1A1, A1A2 or A2A2 for beta casein.
Why does A2 matter?
Studies have found that when a person drinks milk, digestive enzymes interact with A1 and A2 beta-casein proteins in different ways, so they are processed differently within the body. Some believe the A2 gene is more natural, and therefore more healthy. That has led to a recent consumer demand for A2A2 milk.
True A2 milk can only be produced from cattle possessing the A2 gene at both locations. So the one and only determining factor determining whether milk is A1 or A2 lies in the genetic make-up of the animal producing the milk.
The Jersey breed has a slightly higher proportion of animals with the A2A2 genes. However, if you are a Holstein producer who could receive a premium for A2 milk, you can see from this extensive list of A2A2 sires that you don’t have to sacrifice much in terms of genetics or switch breeds to attain that A2 gene preferred by consumers in some parts of the world.