* Breeds have distinct color patterns: Some breeds are known for specific colors. For example, Holstein cows are black and white, Jersey cows are usually fawn (brownish) with white markings, and Guernsey cows are often a light orangey-brown.
* Individual variations: Even within a breed, there can be variations in color. For example, a Holstein cow could have a larger black patch or more white spots than another Holstein.
So, while certain colors are common in specific breeds, it's hard to say which is the "most popular" overall.