The Truth About A1 vs. A2 Milk- And Why It Matters

From our pastures to your glass, we keep it old-fashioned and digestible.

Jaycee, our A2 registered Jersey

If you've ever felt bloated or uncomfortable after drinking milk and just chalked it up to lactose intolerance—let’s talk. It might not be the lactose at all. The issue could actually be something called A1 casein, and it's snuck its way into most of the commercial milk on store shelves today.

Here at Rowdy Rooster Co., every single one of our cows and goats is A2/A2 —meaning the milk we offer is the real, digestible, heritage kind your great-grandma probably drank. But how did our dairies even end up with A1 milk in the first place?

Let’s break it down:

What’s the Difference Between A1 and A2 Milk?

Milk contains a protein called beta-casein, which comes in two main types: A1 and A2.

• A2 beta-casein is the original, naturally occurring protein found in milk from heritage breeds and human breast milk (and goat milk!). It’s gentle on the gut and easier to digest.

• A1 beta-casein is a mutated version that showed up due to poor breeding decisions—mainly in large-scale dairies trying to increase production. This version of the protein can cause inflammation, gut discomfort, and symptoms similar to lactose intolerance in many people.

  
  

When A1 milk breaks down in the digestive system, it produces something called BCM-7, a peptide that has been linked to digestive issues and inflammation. A2 milk? It doesn’t produce that. It's smooth, clean, and nourishing—just the way nature intended.

Why Big Dairies Went A1

The shift toward A1 genetics wasn’t intentional at first—it came from choosing cows that produced higher volumes of milk, regardless of their protein makeup. Over generations, Holsteins (the most common dairy breed in the U.S.) were bred almost exclusively for yield, and A1 genetics slowly took over.

But quantity doesn’t always mean quality.

By ignoring the importance of A2 casein, large dairies bred out one of the most important health-supporting traits milk had to offer. And now we’re seeing the consequences: more people than ever think they “can’t do dairy,” when in reality, their bodies are just rejecting the wrong kind of milk.

Rowdy Rooster Co. — Proudly A2/A2

At Rowdy Rooster, we’re not interested in shortcuts or trends. We’ve intentionally grown our herd with A2 genetics only, both goats and cows, to make sure the milk you’re getting is as close to nature as possible.

We believe in milk that supports your body, not fights it. Milk that your kids can grow up on without tummy aches. Milk that doesn’t need to be processed, stripped, or “lactose-free” because it was never the problem to begin with.

This isn’t just about better milk—it’s about better health, better breeding, and getting back to what dairy should be.

From our ranch to your fridge,

—The Rowdy Rooster Family