According to my agribusiness students, different breeds of cows can indeed have varying proportions of water, fat, and protein in their milk. This implies that there are some discernible differences. However, they mentioned that it becomes more challenging to distinguish these differences once the milk has been pasteurized. In order to maintain consistent taste from day to day, dairies typically blend milk from different cow breeds. This practice helps mitigate any flavor variations that may arise when cows graze on wild garlic or wild onions in the fields during springtime. By mixing milks, dairies aim to minimize the impact of these flavor differences.