How did dairy cows get to America?
By humans importing them from other countries.
A Seasonal dairy is an operation that only has its dairy cows milk for one or two seasons out of the year, unlike the conventional dairy which has cows milking all year round. It is this way that cows have a rest period before they are set to give birth to a calf and give milk for a number of months.
Bos primigenius taurus, primarily. Though there are Bos primigenius indicus dairy cows as well, though they are primarily found in the Middle East, and East Asia and most of Africa. This species of dairy cow is much less common than the Holstein or Friesian which is B. p. taurus, since such animals are used for subsistence dairies, not commercial or large-scale dairies common in Europe, North America, South America and Australia.
Dairy cows are typically thinner cows, more angular in bod structure with large pendulous udders. They do not get as fat or muscular as beef cows do, and are very often more feminine-looking. Color varies according to breed, but the most common dairy cow you will see is the black-and-white cows called Holsteins.