Which dairy cow breeds produce milk with especially high fat and protein levels?

Among the major dairy cow breeds, the Guernsey and Jersey breeds are recognized for producing the milk with the highest fat and protein levels.1

Specifically, the milk from these breeds compares as follows:

• Jersey: This breed produces the richest milk, with an average butterfat content of 5.2 percent. Its protein content is also among the highest, averaging 3.92 percent.1
• Guernsey: Milk from this breed averages about 4.8 percent butterfat and has a protein content of 3.91 percent.1

In contrast, other major breeds generally have lower concentrations of these components. For example, the Holstein-Friesian—which is known for the largest total volume of milk production—has an average butterfat content of 3.7 percent and the lowest protein content at 3.23 percent. The Ayrshire and Brown Swiss breeds both produce milk with an average butterfat content of approximately 4.1 percent.1