Holsteins are the most common breed and are known for outstanding milk production. Holsteins are what most likely comes to mind when thinking about a dairy cow with their classic black and white markings. These markings can also be red and white which is the expression of a recessive gene.
Raw milk from Jersey n Gurnsey cows does NOT produce the A1 protein that most people have lactose allergy to. Black Holstein cows make the undigestable protein but they produce much more milk, so... the BigAg wants those cows. then they boil it, chemical it, strain it, homoginize it and sell you Milk-colored and flavored liquid. Also, true dairy cows are small and pretty! @Cheryl Daniel