The criterion is the cleansing of milk and how much cream it holds. The amount of cream is influenced by the genus of the animal and the addition of water. Holstain varieties (black spotted ones) give too much milk but the milk is not too fat. Dairy companies generally want this animal in the producers. Montofons’ milk is much more fatty and delicious. You should buy milk from enterprises that comply with the cold chain and hygiene conditions, especially in open containers (jug, jerrycan, etc.) and you should avoid the sellers without cooling.