Photo from Vicky Frank's photostream
Yes, there IS a controversy over milk from black cows versus milk from brown cows, but actually it's the A1 milk vs the A2 milk. Color matters.
For several years now scientific testing of milk has been turning up some interesting facts that vary the healthfulness of milk from certain cows. Milk contains casein, which is a protein... more specifically, beta-casein. Beta casein contains an amino acid called BCM-7, a powerful opiate linked to negative health effects such as Type 1 Diabetes, heart disease, neurological impairment including autistic and schizophrenic changes and auto-immune disease.
Beta casein from older breeds of cows (like the brown & white Jersey and Guernsey cows) contains an amino acid called proline. (There will not be a test, so don't worry!) These cows typically produce A2 milk where the proline bonds to the BCM-7, which keeps it OUT of the milk.
In newer breeds of cows like the black & white Holstein cows, the amino acid proline has mutated to one named histadine. Histadine does not bond to BCM-7, so BCM-7 gets INTO the milk; that's called A1 milk and it is typically produced by Holsteins.
Why haven't we heard any of this? It's Easy. Follow the Money... The predominant cow for dairy products in the US is the Holstein cow. No one outside the dairy industry has any interest in paying for milk research, and the dairy industry likely won't pay for the research because it would be financially devastating regarding their herds.
Nonetheless, I understand many American and Canadian breeders are routinely testing herds for A2 genetics and breeding accordingly. There is still much research needed in order to be fully conclusive about A1 or A2 milk and disease.
I'd also like to see some conclusive evidence that grain-fed, pasteurized CAFO (Concentrated Animal Feeding Operation) milk is dangerous. Let us drink healthy raw milk if we so choose!
Because dead milk is dead milk, whether the cow is brown or black, I'll just find someone who sells raw milk from a brown cow and buy half the cow.
For more information: The Bovine; Real Milk.