How milk is produced on a dairy farm

Left to stand, fresh milk separates on its own, as the fat floats up into a cream layer within 12 to 24 hours.

stations: 3
things downstream: 22

The short version

Milk comes from cows kept on dairy farms, and cows have been bred to give far more than a calf needs. Most are milked twice a day, by machine in developed countries. The milk is cooled on the farm and collected for a dairy plant. About 85% of the world's milk comes from cows.

Breed the dairy herd

A cow must calve before she gives milk, and the gestation period is about nine months. Dairy breeds such as the Holstein have been bred selectively for higher milk production, and farms often use artificial insemination.
Milk twice a day

Most cows are milked twice per day. Hand milking in barns gave way to vacuum bucket milkers in the early twentieth century and then to pipeline and automated milking equipment, which now produces the vast majority of milk in developed countries.
Ship it to the dairy

Milk is processed at a dairy, either onsite at the farm or after being shipped. Untreated milk separates on its own over 12 to 24 hours into a fatty cream layer and a larger, low-fat layer, which centrifugal separators now do quickly.

End of the lineRaw milk Next it goes into butter, pasteurized milk, cream cheese and 6 more.

Worth repeating

Pigs are almost never milked, because a sow has many small teats and cannot store her milk the way a cow can.
Dairy farms produced around 730 million tonnes of milk from 260 million dairy cows in 2011.
Water buffalo, goats, sheep and camels also supply milk, with buffalo providing about 11% of the world total in 2011.